Joint Coho Technical Committee Periodic Report

Author

PSC Joint Coho Technical Committee

Published

February 4, 2025

Coho Picture

1 Introduction

In response to a decline in natural Coho Salmon (Onchorynchus kisutch) abundance, the Pacific Salmon Commission (PSC) established a Southern Coho abundance-based management regime (CoABM) in 1999 (Pacific Salmon Commission 1999). This Southern Coho Management Plan (SCMP, also referred to as ABM, or ‘abundance based management’) aimed to conserve Coho Salmon Management Units (MUs) of naturally-spawning Coho Salmon in southern British Columbia and Washington/Oregon based on abundance status and escapement goals. The set out to constrain exploitation rates (; defined as total fishing mortality divided by total fishing mortality plus escapement) below maximum levels (caps) on selected in order to achieve long-term Maximum Sustainable Harvests (MSH). These constraints are implemented by specifying caps for the individual dependent on annual abundance status. During their respective preseason planning processes, the Parties use management reference points to classify the status of each as low, moderate, or abundant. The parties then exchange these status determinations as a key input in the development of pre-season plans.

When a new Coho Management Plan was agreed upon in 2008 (implemented 2009 through 2018; (Pacific Salmon Commission 2009)) and the latest agreement finalized (applies to the period from catch years 2019 through 2028; (Pacific Salmon Commission 2022)), modifications were made to the list of specified and to the manner in which caps are established. This periodic report presents information for the identified in the most current Pacific Salmon Treaty’s (PST) (Chapter 5 of Annex IV in the current ). In the 2008 abundance-based management regimes were established to constrain () on 13 of naturally-spawning Coho Salmon originating in rivers along the Washington/British Columbia (BC) border. Beggining in 2019, the most recent Management Plan (Pacific Salmon Commission 2022) combined two of the Canadian , the Georgia Strait Vancouver Island and the Georgia Strait Mainland into the Strait of Georgia . The 12 in the current are listed below (Table 1.1).

Table 1.1: Management Units within the current Pacific Salmon Treaty Southern Coho Management Plan.
Southern BC US Inside US Outside
Interior Fraser Skagit Quillayute
Lower Fraser Stillaguamish Hoh
Strait of Georgia Snohomish Queets
Hood Canal Grays Harbor
US Strait JDF

The objective of the , as described in the Treaty, is to manage salmon directed fisheries impact on Southern Coho stocks by limiting the total fishery exploitation and allow the different to produce long-term , while maintaining the genetic and ecological diversity of the individual populations. In addition, the plan is designed to improve the prospect of sustaining healthy fisheries for both parties over the long-term. The plan is intended to be cost-effective and flexible to available technical capacity and information, while providing a predictable framework for planning fisheries impacts and allowing for objective monitoring, evaluation and modification.

Under the Agreement, the United States and Canada (the “Parties”) are required to establish escapement goals or that achieve , determine for each , and establish for each and status category (low, moderate, and abundant). Until such time as the Parties provide -specific targets, the identified default ceilings for the following status categories:

Table 1.2: Status categories for MSH
Status Total Exploitation Rate
Low Up to 20%
Moderate 21% - 40%
Abundant 41% - 65%

Annual caps are established for each of the based on the level of abundance and health of the natural stocks. These caps are then apportioned between the Parties. Constraints for Canadian fisheries on US are determined by formulas that specify sharing of allowable as well as a composite rule, which together adjust caps according to the number of US MUs that fall within a given category. The composite rule adjusts constraints for Canadian fishery based on the number of US which fall in a given category. For example, if only one Washington coastal or Puget Sound Coho is in low status, Canadian fisheries are constrained to a total on that unit of 12%; if two or more Washington coastal are in low status, the constraint becomes 10%. The most restrictive limit for Canadian fishery impacts on US Coho is 10%.

Constraints for US fisheries on Canadian depend on the status of the Interior Fraser until the biological statuses of the other Canadian have been determined. The status determination methodology developed and applied by Canada to the Interior Fraser Coho (REFERENCE Korman and Sawada) consists of two criteria: smolt-to-adult survival, and escapement, which must be met for three consecutive years in order increase the status from low to moderate or moderate to high. Canada is currently working to develop the information (smolt to adult survival rates, escapements) needed to apply this status determination methodology to the Lower Fraser and Strait of Georgia . Details as to how constraints are established based on the status of under the are contained in Annex IV Chapter 5 Section 9.b-c (Canadian caps on inside and outside US ) and Section 9.d (US caps on Canadian ).

1.1 Management Unit Overview

The Canadian are comprised of geographical aggregates of naturally spawning Coho conservation units (CUs) within the Interior Fraser River, Lower Fraser River, and Strait of Georgia. A consists of one or more spawning populations which are genetically distinct from other conspecific spawning populations. The 2019 renewal of the combined the Georgia Basin – East and Georgia Basin – West into a single Strait of Georgia , reducing the number of Canadian in the bilateral management regime to three. The CoTC chose to combine model outputs for these in carrying out its pre-season and post-season responsibilities beginning in 2019 and forward rather than reconfigure the FRAM framework.

The US Inside consist of naturally spawning populations originating in the Skagit, Stillaguamish, Snohomish, Hood Canal, and the Strait of Juan de Fuca. Coho populations in the US Inside belong to the larger Puget Sound/Strait of Georgia Coho Salmon evolutionarily significant unit (ESU; (Weitkamp et al. 1995)). Only the eastern portion of the Strait of Juan de Fuca is in this ESU. An ESU is a Pacific salmon population or group of populations that is substantially reproductively isolated from other conspecific populations and represents an important component of the evolutionary legacy of the species. The ESU policy (56 FR 58612) for Pacific salmon defines the criteria for identifying a Pacific salmon population as a distinct population segment, which can be listed under the US Endangered Species Act of 1973.

The US Outside consist of naturally-spawning populations from the Quillayute, Hoh, Queets, and Grays Harbor basins. All US Outside , except the Grays Harbor , are part of the Olympic Peninsula ESU. Populations from the western portion of the Strait of Juan de Fuca are also in this ESU. The Grays Harbor is part of the Southwest Washington ESU.

1.2 Fishery Overview

Under the CoABM regime, each Party is required to regulate its fisheries so as not to exceed constraints on . Fishery Management Areas for British Columbia (Figure 1.1), Washington (Figure 1.2), and Oregon (Figure 1.3) are shown below.

Figure 1.1: Canadian DFO Southern BC Pacific Fisheries Management Areas.
Figure 1.2: Washington Coast and Puget Sound Marine Fishery Areas.
Figure 1.3: Oregon Ocean Salmon Management Areas and Major Port Locations.

1.2.1 Canadian Fisheries

Request for input

Southern BC Coho Salmon are caught in First Nations, recreational, and commercial troll and net fisheries. Since Coho Salmon rear in areas near the coast they are readily caught in directed fisheries and as bycatch in fisheries targeting other species. As a result, Coho Salmon are harvested in mixed-stock fisheries, creating many challenges for the assessment and management of the species.

Coho Salmon catches on the south coast of BC have declined since the mid-1980s, initially due to declining abundance and more recently because of severe conservation measures in response to the declining abundance. Total fishery in Canada were reduced from a range of 75 to 80% in the mid-1980s to 60% in 1995, 37% in 1997, 5% in 1998, and are currently estimated by Backwards Coho Fisheries Regulation Assessment Model (FRAM) during catch years 2011 through 2021 at less than 10%.

Historically 89% of the commercial Coho Salmon catch on the south coast of BC was taken by the troll sector with the remainder harvested by commercial net fisheries. The West Coast of Vancouver Island (WCVI) troll fishery was the single largest commercial harvester, taking an average of 1.5 million Coho Salmon in the 10-year period before 1997, when major fishing restrictions were imposed. This fishery intercepted stocks from the US, Strait of Georgia, and WCVI. Since 2001, average catch retained in the WCVI troll fishery has been 725 Coho, due primarily to the timing and non-retention restrictions in place for this fishery. Historically, catch in the Strait of Georgia troll fishery, comprised predominantly of Strait of Georgia stocks, was much smaller than the WCVI troll fishery (1986-1995 averaged 150,000 Coho Salmon, annually). The Strait of Georgia troll fishery has not been permitted to retain Coho Salmon since 1995.

Net fisheries in Johnstone Strait, Strait of Juan de Fuca and the Strait of Georgia harvest Coho Salmon incidentally during directed fisheries on Sockeye (O. nerka), Pink (O. gorbuscha), and Chum (O. keta) Salmon. Net fisheries have been curtailed in recent years due to low returns of the target species and concerns for Chinook (O. tshawytscha) and Coho Salmon bycatch.

While the First Nations’ harvest of Coho Salmon is small compared with other salmon species, several First Nations harvest Coho Salmon for food, social, and ceremonial purposes. They are caught in hook and line, net, and spear fisheries in or near their local streams. They are also caught incidentally in other First Nations’ salmon fisheries directed on other species, such as Sockeye and Chum Salmon.

Recreational fishing for Coho Salmon in BC tidal waters continues to be important to residents and visitors. Until the recent decline in Coho Salmon abundance and subsequent severe fishing restrictions, 70% of tidal recreational fishing took place within the Strait of Georgia. Since 1995, most Coho Salmon recreational fishery effort and catch has shifted from the Strait of Georgia to the WCVI, in part due to low abundance of Coho Salmon inside Vancouver Island. Overall, the proportion of Coho Salmon harvested by the recreational fishery has increased as commercial harvest has been significantly reduced as a result of the timing and non-retention harvest restrictions, as well as domestic allocation considerations in Canada that were implemented in response to the low abundance of Coho Salmon.

Due to conservation concerns, most notably for the Interior Fraser , Canadian Coho Salmon fisheries have seen unprecedented restrictions since 1997. In 1998 and 1999, no directed fisheries on naturally-spawning stocks of Coho Salmon were permitted; mandatory non-retention and non-possession of incidentally caught Coho Salmon was implemented in all areas, with the exception of some terminal hatchery locations. In the Pacific Region, (i.e., all marine waters of BC), barbless hooks became required for all salmon-directed commercial and recreational hook and line gear in 1998, a regulation that remains in effect. Pacific Region waters were classified as red or yellow zones. In red zones, areas where Thompson River Coho Salmon from the Interior Fraser River were known to be prevalent, fishing was restricted to very limited experimental selective fisheries, as well as some limited First Nations’ fisheries to meet food, social, and ceremonial requirements. Red zones included inshore waters of Victoria to Barkley Sound and offshore waters of Barkley Sound to Quatsino Sound, from June to September. Special management zones (SMZs), areas of mandatory Coho Salmon non-retention with special restrictions, were identified with the intent to avoid Coho Salmon encounters. Fisheries were only permitted in locations and times when Thompson River Coho Salmon could be avoided or released unharmed. These areas were subject to in-season adjustments, including time and area closures for all sectors. Fisheries conducted in these SMZs were monitored to ensure Coho Salmon encounter rates did not become too high, and tissue samples were taken for stock identification. In yellow zones, where endangered stocks were not prevalent, a selective fishing strategy was implemented for all commercial and recreational fisheries [Jeromy comment: Does this mean in red zones, endangered stocks (under SARA?) are prevalent? This context is not provided.]. These fisheries were required to release any live Coho Salmon Salmon that were caught during operations. Mandatory logbooks and an onboard observer program were initiated in commercial fisheries. Limited Coho Salmon retention was allowed only for First Nations and recreational fisheries.

Since 2000, fisheries impacting naturally-spawning Coho Salmon from southern BC, Washington State, and Oregon have been managed under the ABM regime. The ABM plan constrains total fishery exploitation on key stock in BC For each , annual limits of fishing mortality are established based on the categorical level of abundance and the health of the naturally-spawning stocks. In Canada, low status of Interior Fraser Coho Salmon has constrained southern BC fisheries for the last decade. The Southern US has been limited to 10% on Coho Salmon originating from the Interior Fraser . Southern BC fisheries, in waters south of Cape Caution where Interior Fraser Coho Salmon are prevalent, have been managed to a maximum 3% total fishing mortality rate on the Interior Fraser Coho Salmon . Non-retention of naturally-spawning Coho Salmon is generally in effect except for First Nations opportunities in specific terminal systems where abundance permits and where retention of by-catch during fisheries for other species is permitted. Release of unmarked Coho Salmon during periods when Interior Fraser Coho Salmon may be caught is required in all Canadian commercial and recreational fisheries.

1.2.2 US Fisheries

Current US fisheries are constrained by domestic and conservation objectives. For the Puget Sound , the current of CoABM uses the thresholds and stepped harvest rate goals from the Comprehensive Coho Agreement (Comprehensive Coho Workgroup 1998), developed by Washington State and the Puget Sound tribes, and adopted by the as Fishery Management Plan conservation objectives in November 2009. Actual constraints for Canadian fisheries on US Coho Salmon are determined by formulas that specify sharing of allowable total and a “composite rule”. The composite rule adjusts constraints for Canadian fishery based on the number of US that fall in a given category. For example, if only one Washington coastal Coho Salmon is in low status, Canadian fisheries are constrained to a total on that unit of 12%; if two or more Washington coastal are in low status, the constraint becomes 10%. The most restrictive limit for Canadian fishery impacts on US Coho Salmon is 10%.

Fisheries between Cape Falcon, Oregon and the US/Canada Border are constrained by four factors: (1) management objectives and treaty Indian obligations for individual stock US MUs; (2) treaty Indian/non-Indian and ocean/in-river sharing agreements; (3) stocks listed under the ESA; and (4) requirements of the . The starting point for implementing these constraints is the forecasted January age-3 (JA3) abundance and the modeled ocean distribution of each Coho Salmon stock.

Most Coho-directed recreational fisheries [Jeromy comment: Freshwater and marine? I think so, for WA, and Columbia River but would be good to add this qualifier in if true. More recently the OR coast freshwater fisheries are all non-selective, hence why I am asking for a bit of a qualifier here if possible.] have been mark-selective since 1999. Non-Indian commercial troll fisheries have been mostly restricted to mark-selective Coho Salmon retention since 2000. Treaty Indian fisheries are not restricted to mark-selective retention of Coho Salmon.

1.3 Bilateral Assessment Tool (FRAM) Overview

Coho Salmon fisheries are evaluated with the Coho Fisheries Regulation Assessment Model (Coho FRAM), a bilaterally developed tool that is employed for both pre-season fishery planning and post-season estimation of escapements and (see: pre- and post-season applications).

Coho FRAM is an annual mixed-stock accounting model that evaluates a set of stock units within a set of fisheries over time periods within a single fishing year (the calendar year for Coho Salmon) (documentation on FRAM can be found here: https://framverse.github.io/fram_doc/). It can be used to estimate catch and escapement based on forecast abundance and planned fisheries (‘forward’), or it can be used to reconstruct ocean abundance from observed escapements and fisheries (‘backward’). ` The Coho FRAM base period parameterization, determining stock-fishery-timestep impacts, was constructed from stock-specific fishery recoveries of coded-wire tags within the time steps January to June, July, August, September, and October to December during coast wide fisheries from 1986 to 1992. The procedure used to generate base period data is depicted below (Figure 1.5). For each base period year, post-season reconstruction of cohort abundances for each Coho Salmon is based on two different models: the Mixed-Stock Model (MSM) that estimates the Production Expansion Factors for each Production Region and Terminal Area Run Reconstruction (RRTERM) program that estimates stock-specific impacts for terminal marine and freshwater fisheries. The MSM uses recoveries for each model stock expanded by the Production Expansion Factors to best describe the total catch in each marine mixed-stock fishery. The MSM/ cohort analysis has been used for post-season reconstructions for catch years 1986-2007. However, beginning with catch year 1993, too few coded-wire tags were recovered in mixed-stock fisheries to perform robust cohort analyses using the mixed-stock model (Figure 1.4).

Figure 1.4: Total preterminal tag recoveries for all Coho Salmon ages 3 and 4 (regardless of clip status).
Figure 1.5: Procedure used to generate base period data for Coho FRAM.

1.3.1 Key Uncertainties with FRAM analysis

FRAM is a deterministic model that reports point estimates of cohort abundances and without explicit measures of uncertainty associated with them. Managers should consider the following data limitations and model assumptions when interpreting FRAM results:

  • Cohort abundances and are sensitive to the quality of escapement estimates, with estimation practices varying substantially among stocks. For example, Puget Sound net pens programs often lack escapement estimates. For these programs, pre-season abundances were used or were scaled to a nearby hatchery program using a pre-post ratio.
  • Marine survival indices are used to estimate Canadian abundances, except for Interior Fraser, in both pre- and post-season FRAM runs because abundance forecasts and escapement estimates are highly uncertain or unavailable for the remaining two Canadian MUs.
  • It is unknown if average ocean distribution during the FRAM base period (derived using catch year 1986 to 1992 data) reflect the true annual ocean distribution of Coho Salmon stocks in contemporary years; this leads to increased uncertainty in fishery-specific stock impacts.
  • Complex regulations, such as fine-scale spatial/temporal and mixed retention limits for natural and hatchery Coho Salmon within a fishery, are difficult to represent and assess within FRAM and as a result, FRAM may not accurately represent stock-specific impacts within fisheries with these regulations.
  • Spatial and temporal gaps in catch monitoring of some Canadian fisheries result in underestimation of catch.
  • Uncertainty in mortality estimates arises from several sources, including creel census and catch estimation.
  • Within time steps in FRAM, natural mortality is constant; additionally, natural mortality does not reflect inter-annual variability in survival during adult ocean residence (January Age-3 through FRAM’s final time step).

For more details, see the FRAM documentation.

2 Determination of Status Benchmarks and ER Caps

2.1 Canadian Management Units (this needs to be updated)

Procedures for determining the pre-season status of Canadian are being developed concurrently with determination of Conservation Unit (CU) status benchmarks required with implementation of the Canada Department of Fisheries and Oceans’ (CDFO) Wild Salmon Policy. Methods have been approved through the ’s internal peer review process, Center for Scientific Advice - Pacific (CSAP) (Holt et al. (2009)). Work in 2018 identified a framework to develop potential Management Reference Points for Canadian (DFO 2018, Korman et al. 2019; https://www.pac.dfo-mpo.gc.ca/consultation/smon/pst-coho-tsp/index-eng.html) included spawner abundance targets but also smolt-to-adult (or “marine”) survival index targets. It was deemed that targets must contain spawner abundance targets, which limited creation of management reference points to the Interior Fraser River because it was the only unit with an aggregate abundance timeseries.

Since 2002, in the absence of benchmarks, the Stock Assessment staff has provided a categorical outlook for the next year’s salmon status. The outlook is intended to provide an objective and consistent context within which to initiate fisheries planning.The category reflects the current interpretation of existing quantitative and qualitative information, including pre-season forecasts if available, and the opinion of Area stock assessment staff. Where management targets for stocks have not been formally described, interim targets were either based on historical return levels or, if necessary, opinion of local staff.

Canadian Coho Salmon abundance has declined, particularly in southern BC. Interior Fraser River Coho Salmon was assessed as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in2002 and then reassessed as threatened in 2016. Interior Fraser River Coho Salmon have not been listed on Schedule 1 of the Species at Risk Act, which would afford additional protections to the stock. However, the Canadian Minister of Fisheries and Oceans has established a domestic cap of 3-5% for Canadian fishery impacts on Interior Fraser Coho Salmon. The Interior Fraser is comprised of five (North Thompson, South Thompson, Lower Thompson, Fraser Canyon, and Upper Fraser). The Interior Fraser River Coho Salmon recovery planning process has determined the critical benchmark needed to maintain population viability. Even with the reduction in fisheries exploitation, all Southern BC have followed a similar dramatic declining trend in both marine survival and total abundance from the high levels observed in the 1980s and early 1990s. Spawning escapements have responded to the decreased exploitation and are within the range observed during the 1970s and 1980s. However, the sustained low marine survival has resulted in a decreased total abundance.

Because of the absence of programs to estimate total abundance and escapement for the Strait of Georgia and Lower Fraser River Canadian , the bilaterally-developed tool, Backwards Coho FRAM, is relied upon to generate estimates of ocean age-3 cohort abundance and using post-season data scalars. Cohort abundances (catch and escapement) of Canadian , estimated by Backwards Coho FRAM based on modeled scalars, are depicted in Figure Figure 4.1. Reduced abundances apparent since 1996 were a major consideration that led to the development of ABM regimes for management of southern Coho Salmon.

2.2 US Inside Management Units

The status for US Inside is assigned based on ocean abundance (forecasted or re-constructed). Pre-season estimates of ocean abundance are typically forecasted from measured or modeled smolt production for each and multiplied by a marine survival rate predicted for each . Marine survival is predicted with a variety of methods including average return rates, correlations between jack and adult return rates, and correlations between environmental variables and historical return rates. Post-season estimates of ocean abundance are estimated using escapement and catch data and the Backwards Coho FRAM (Figure 4.2). The status of each is defined by a series of ocean abundance breakpoints. Domestic management of Puget Sound naturally-spawning Coho Salmon stocks also uses abundance-based, tiered objectives defined in the Comprehensive Coho Plan (Comprehensive Coho Workgroup 1998), that are similar to but not exactly consistent with the guidelines. The identified break points between Low, Moderate, and Abundant status are based on population-specific productivity analyses conducted by the state and tribal co-managers in each river basin.

2.3 US Outside Management Units

The status for US Outside is assigned based on the ceiling identified annually, ocean abundance, and existing escapement goals (Pacific Salmon Commission 2022). Management objectives are expressed as a range of spawning escapements expected to produce MSY (Pacific Fishery Management Council 2023a). Allowable are calculated from the forecast abundance and the lower end of the existing escapement goal range and used to classify the categorical status of the . This rate is the maximum allowed under the when the is in the moderate or abundant status, but up to 20 percent are allowed if the is in the low abundance status.

Pre- and post-season ocean abundances are estimated with the same approach described for the US Inside (Figure 4.3). Escapement goals for the US Outside are defined by state and tribal co-managers in each river basin and include escapement ranges in all but one (Grays Harbor) . Escapement ranges were originally intended to reflect the range of uncertainty in the escapement goals identified for each of these populations. Unlike the US Inside , escapement goals for the US Outside do not vary with run size. The escapement goals used for status determinations are the floor of the designated escapement ranges (see Table: @ref(tab:OutsideMUABM)). The stock status is “Low” if the ocean abundance is low enough that the ceiling falls at or below 20% in order to achieve the bottom end of the escapement range. The stock status is “Moderate” if ocean abundance results in an ceiling between 21% and 40%. The stock status is “Abundant” if ocean abundance results in an ceiling above 41%.

2.4 US Management Units Federal Status

Coho Salmon were the first Pacific salmon species for which coast-wide evolutionarily significant units (ESUs) were delineated (Ford 2011). Based on genetic and life history information, the US subject to the belong to three different Coho Salmon ESUs, the Puget Sound/Strait of Georgia, the Olympic Peninsula, and the Southwest Washington ESUs. The Puget Sound/Strait of Georgia Coho Salmon ESU is currently a species of concern under the US Endangered Species Act (ESA; Ford (2011); Species of Concern 4/15/04, 69FR19975). The Olympic Peninsula ESU was evaluated for listing under the ESA and was determined to be not warranted (60 FR 38011; July 25). The Southwest Washington ESU is currently categorized as “undetermined”. Puget Sound/Strait of Georgia Coho Salmon are not currently candidates for listing in Washington as State Endangered, Threatened, or Sensitive (Washington Department of Fish and Wildlife 2020).

At the federal level, species of concern do not have formal protection under the ESA. The primary purpose of identifying species of concern is to prevent the need to list them as threatened or endangered under the ESA. This purpose can be achieved by the following actions: (1) identifying species potentially at risk; (2) increasing public awareness about those species; (3) identifying data deficiencies and uncertainties in species’ status and threats; (4) stimulating cooperative research efforts to obtain the information necessary to evaluate species’ status and threats; and, (5) fostering voluntary efforts to conserve the species before listing becomes warranted.

Additionally, at the federal level, Coho Salmon caught in coastal waters of the U.S. (e.g., greater than 3 but within 200 nautical miles offshore) are managed under the Magnuson-Stevens Fishery Conservation and Management Act (MSA), which is the legislation providing for the management of marine fisheries in U.S. waters. In 2018, the National Marine Fisheries Service (NMFS) notified the that the Strait of Juan de Fuca, Queets, and Snohomish natural Coho Salmon stocks managed under the ’s Pacific Coast Salmon Fishery Management Plan (FMP) met the overfished criteria of the FMP and the MSA. NMFS determined that these stocks were overfished under the MSA, due to spawning escapement falling below the required level for the 3-year period 2014-2016. The MSA requires overfished stocks to be rebuilt in as short a time as possible, not to exceed 10 years. The overfished determinations were announced in the Federal Register on August 6, 2018 (83 FR 38292). In response to the overfished determination, the developed rebuilding plans for these stocks and provided them to NMFS in 2019. In 2021, NMFS issued a final rule under the authority of the MSA to approve and implement rebuilding plans recommended by the for the three stocks (86 FR 9301). This final rule adopts the existing harvest control rules, which use an annual abundance-based stepped harvest rate control rule with stock-specific abundance levels governing the total applied to forecast stock abundance levels. For Snohomish natural Coho Salmon, this final rule amends the existing harvest control rule by adding a 10% buffer to the existing escapement goal and adjusting the abundance steps during the rebuilding period. For all three Coho Salmon stocks, the ’s Salmon Technical Team’s analysis determined that freshwater and marine habitat conditions were the primary cause of these stocks meeting the FMP’s criteria for being overfished rather than fishing. Recently, it was determined that the Queets and Strait of Juan de Fuca have met the criteria for rebuilt status based on the most recent three-year geometric mean of escapement estimates (2020-2022) (Pacific Fishery Management Council 2024a).

3 Annual Implementation of the Southern Coho Management Plan

The Coho FRAM (Coho FRAM, Model Evaluation Workgroup (MEW). 2008) has been the tool used to plan US preseason fisheries, and also to evaluate postseason by the fisheries of both Parties on the naturally spawning Coho Salmon specified by the CoABM. Canada has not been using Coho FRAM preseason, instead using a combination of a ‘domestic model’ for planning marine fisheries and a ‘decay model’ for planning Fraser River fisheries. (Jeromy’s comment - Can we describe what get’s exchanged during the preseason process to reconcile this difference here in one or two sentences?)

Each country manages the Coho Salmon harvest within its cap through its own domestic fisheries management processes and annual fisheries plans. For Canada, the annual domestic planning process is documented in the salmon Integrated Fisheries Management Plan (IFMP) at the culmination of the process each June (is June correct?). For the US, the North of Cape Falcon ocean salmon fishing plans are reported in Preseason Report III (PFMC documents) at the culmination of the process each April. For US Inside , the 2019 uses the thresholds and stepped harvest rate goals from the Comprehensive Coho Agreement and adopted as (Fishery Management Plan) FMP conservation objectives in 2009. For US Outside , constraints represent the Maximum Fishing Mortality Threshold (MFMT). For US domestic purposes, the status categories are “critical”, “low”, and “normal”, which correspond to the categories of “low”, “moderate” and “abundant”, respectively (Pacific Fishery Management Council 2024b).

The US FMP includes status determination criteria (SDC) for overfishing, approaching an overfished condition, overfished, not overfished/rebuilding, and rebuilt (Pacific Fishery Management Council 2023b). These criteria are:

  • Overfishing occurs when a single year exceeds the maximum fishing mortality threshold (MFMT), which is based on the maximum sustainable yield (FMSY);

  • Approaching an overfished condition occurs when the geometric mean of the two most recent postseason estimates of spawning escapement, and the current preseason forecast of spawning escapement, is less than the minimum stock size threshold (MSST);

  • Overfished status occurs when the most recent 3-year geometric mean spawning escapement is less than the MSST;

  • Not overfished/rebuilding status occurs when a stock has been classified as overfished and has not yet been rebuilt, and the most recent 3-year geometric mean spawning escapement is greater than the MSST but less than Sustainable Maximum Yield (SMSY; the number of spawners need to maintain the highest possible annual catch of a population, a biological benchmark that represents a healthy population);

  • A stock is rebuilt when the most recent 3-year geometric mean spawning escapement exceeds SMSY.

Queets natural Coho Salmon, Strait of Juan de Fuca natural Coho Salmon, and Snohomish natural Coho Salmon stocks were classified as overfished in 2018, and the adopted rebuilding plans for these stocks in 2019 (Pacific Fishery Management Council 2023a). In 2020, Snohomish natural Coho Salmon was reported to have met the criteria for not overfished/rebuilding. In 2023, Snohomish natural Coho was reported to have met the criteria for rebuilt and Strait of Juan de Fuca natural Coho Salmon was reported to have met the criteria for not overfished/rebuilding. Queets natural Coho Salmon continue to meet the criteria for overfished. Coho Salmon fisheries, particularly north of Cape Falcon, were shaped to minimize impacts on these stocks and meet the objectives of the rebuilding plans. Objectives of the rebuilding plans for Queets natural Coho Salmon and Strait of Juan de Fuca natural Coho Salmon are to manage the stock under status quo SMSY.

3.1 Annual Determinations of Allowable Exploitation Rates for Management Units

3.2 United States fishery Planning Process

The US annual salmon fishery planning process starts in January with a Stock and Fishery Evaluation (SAFE) report on fisheries and escapements from previous years and concludes in early April when preseason fishing plans for US fisheries are developed. Outlined below are the Coho FRAM inputs used within the US domestic process to plan annual Coho Salmon fisheries, and postseason data needed to evaluate the preseason plan.

Preseason FRAM inputs:

  • Stocks’ abundance forecasts
  • Fishery inputs by Coho FRAM time period (e.g., season structure, gear and retention restrictions, quota levels, fishery harvest rate scalars)

Inseason:

  • FRAM fishery adjustments

Postseason FRAM inputs:

  • Stocks’ observed escapement
  • Fisheries’ observed catch and non-retention mortality by FRAM time period

Because the domestic planning processes of the Parties are not synchronous, a single pre-season command file containing expectations for both Canada and the US is not available prior to the conclusion of the process (US pre-season fishery planning) in April. Therefor, in any given year the pre-season command file used by the incorporates cohort abundance for both Canadian and US , but planned fishery regulations for US fisheries only. Unless other information is available, Canadian regulations are assumed to be similar to those implemented in the previous year. Subsequent to this process, additional command files are generated to represent the actual Canadian fishing plans. Command files used in pre-season planning from 2004 to 2023 are detailed in Table 3.1. These files contain specific information used at the time to model fisheries along with the pre-season forecasts of stock abundances.

Table 3.1: Pre- and post-season command files and base period used in FRAM to evaluate over catch years 2004 through 2023. “Post-season Original” command files are those used to generate estimates for the Annual Report provided to the Southern Panel during the Annual Meeting.
Catch Year Pre-season U.S. Pre-season Canada Post-season Original Post-season Revised Base Period Used in Revised BKFRAM Run
2004 0425.Cmd 0427.Cmd 04pa.Cmd BK04.Cmd CohoBase
2005 0519.Cmd P5at.Cmd 05p9bk.Cmd BK05.Cmd CohoBase87917
2006 0619.Cmd 0631.Cmd 06p4.Cmd BK06.Cmd CohoBase-86-92-NoUF86-Jan2008
2007 0714.Cmd 0714.Cmd 07JH.Cmd BK07.Cmd CohoBase-86-92-NoUF86-Jan2009
2008 0824.Cmd 0828.Cmd BK08.Cmd BK08.Cmd CohoBase-86-92-NoUF86-Feb2008
2009 0920.Cmd 0920.Cmd BK09.Cmd BK09.Cmd CohoBase-86-92-NoUF86-Feb2009
2010 1016.Cmd 1016.Cmd BK10 PSC Feb14 TBD CohoBase-86-92-NoUF86-Feb2009
2011 1116.Cmd TBD Coho2011Post_PSC 2013 TBD TBD
2012 1229.Cmd TBD Coho2012Post_PSC SSNPx2 Q 2014 TBD TBD
2013 bc-1323 all FRAM inputs TBD bk 2013 Final ver3 Feb 11 2015 TBD TBD
2014 bc-Coho1418 US and BC preseason 2014 TBD bc-BK2014 w TAMM inputs final#2 TBD TBD
2015 bc-Coho 1523 Final TBD bc-bkCoho2015 Final TBD TBD
2016 bc-Coho1637 rerun by CoTC TBD bc-BK2016 BPMar2013 final TBD TBD
2017 bc-Coho1731_Final TBD bc-BK Coho 2017 final take2 TBD TBD
2018 bc-Coho1830 TBD bc-BKCoho2018_A_2_a TBD TBD
2019 bc‐Coho1925 TBD bc‐BKCoho2019_A_2_d TBD TBD
2020 bc‐Coho2032 TBD bc‐BKCoho2020_A_2_c TBD TBD
2021 bc‐Coho2140_Final TBD bc‐BkCoho2021_A_2 TBD TBD
2022 TBD TBD Not yet available Not yet available Not yet available
2023 TBD TBD Not yet available Not yet available Not yet available

3.2.1 US Preseason Abundance Forecasts

US forecast development commences in January of every year. US Forecasts for both Coho and Chinook Salmon stocks are finalized in late February and published in the annual ’s Pre I Report (https://www.pcouncil.org/salmon-management-documents/#access-salmon-safe-and-management-documents-toc-7e081b15-e1b0-409d-a12e-1a77c0b34e2b). In mid-March, the Parties share general expectations for stock abundance and fisheries though a manager-to-manager information exchange (see Development of Canadian Preseason Coho FRAM Inputs). These forecasts are then used throughout the /NOF (North of Falcon) salmon fishery planning meetings which conclude at the April meeting.

The forecast methodologies for many US stocks’ are generally based upon the products of two estimates specific to each production source: 1) number of smolts leaving freshwaters; and, 2) expected regional marine survival rates. Numbers of naturally produced smolts are estimated in a variety of ways but are based upon a large and widely distributed system of smolt traps. The number of smolts released from hatcheries are known. Marine survival is defined as, and calculated from, catch plus escapement from data. Sibling relationships, between jack returns and subsequent return to the mature cohort, have also been used as an index to predict marine survival. Environmental conditions have been increasingly relied upon as predictors of anticipated survival from smolt to adults entering the fisheries.

In recent years, a variety of preseason abundance estimators have been employed for Puget Sound and Washington coastal Coho Salmon stocks, primarily based on smolt production and survival (Pacific Fishery Management Council 2023b). These estimators are used to forecast preseason abundance of adult Ocean Age 3 recruits. Forecasts for natural Puget Sound Coho Salmon stocks were generally derived by measured or predicted smolt production from each major watershed or region, multiplied by stock-specific marine survival rate predictions based on a jack return model from the WDFW Big Beef Creek Research Station in Hood Canal, natural Coho Salmon tagging programs at Baker Lake (Skagit River basin) and South Fork Skykomish River, adult recruits/smolt data generated from the WDFW Deschutes River Research Station, or other information.

3.2.2 Development of US Preseason FRAM Inputs

US fishery planning relies upon both the Coho and Chinook FRAM models. The process starts at the early March meeting, proceeds through March at a variety of regional meetings (including the NOF meetings), and concludes in early/mid April at the next meeting.

US Coho FRAM Stock Abundance Inputs: Abundance forecasts are incorporated into two models, Coho FRAM and Chinook FRAM, both of which rely on similar algorithms and common computer code. Mass marked and unmarked naturally and hatchery produced stocks (components of ) are represented in US Coho FRAM (e.g., Queets naturally produced unmarked, Queets naturally produced marked, Queets hatchery unmarked, Queets hatchery marked). For the specified by the CoABM, appropriate unmarked naturally produced stocks are combined. Numeric forecasts for southern US Coho Salmon stocks are provided from regional managers which utilize a variety of methodologies. The annual forecasts of Coho FRAM stocks are entered as Abundance Scalars, applied within the model to Base Period Stock Abundance.

Prior to the March meeting, an initial Coho FRAM model run with last year’s planned fisheries and the current year’s US forecasts serves to inform, in a general sense, how the fishery plan from the previous year needs to change to accommodate the current year’s stocks’ abundances. The results from this model run are included in the ’s Pre I Report (for these reports see: https://www.pcouncil.org/salmon-management-documents/#access-salmon-safe-and-management-documents-toc-7e081b15-e1b0-409d-a12e-1a77c0b34e2b).

Starting with this initial model run, the US domestic salmon planning process is affected by the timing and quality of forecasts for Canadian Coho Salmon stocks. Coho FRAM performs best when data for all stocks are incorporated. The US domestic process is, in theory, at the half way point before Canadian forecasts are provided and combined with US forecasts for FRAM modeling at the NOF 2 meeting in late March. Thus, at the March meeting and the NOF 1 meeting there is hesitation to fully use the FRAM results for planning domestic fisheries as those results will likely change when Canadian forecasts are incorporated.

US FRAM Fishery Inputs: Expected fishery catch and/or mortality is the other major category of preseason inputs to Coho FRAM. At the March meeting three options (e.g., catch levels, retention restrictions, harvest rate scalars, seasons) are developed (low, moderate, high) for the US ocean fisheries (California, Oregon, and Washington coasts). The FRAM results for both Coho and Chinook Salmon from these March options are published in the annual PFMC Pre II Report.

During the course of March and early April US meetings, the NOF domestic planning refines fishery inputs to insure compliance with various agreements. These include the Salmon FMP, domestic and international treaties; and the US ESA which collectively establish constraints on fishery impacts upon US Coho and Chinook Salmon stocks.

For the ocean fisheries the model inputs are Catch Quotas and regulations such as mark-selective fisheries, with the expectation that subsequent inseason monitoring will close fisheries without exceeding quotas. The model inputs for most sport and commercial US Puget Sound marine and terminal area fisheries are expected catch or expected harvest rates, generally based upon recent year averages and anticipated fisheries for Fraser Sockeye, Pink and Chum Salmon, and regulations such as mark selective fishing. In some cases the Catch Quota management approach is also used within Puget Sound with planned fishery closure as inseason observations indicate FRAM total fishery mortality estimates are being approached. The mortality associated with Coho Salmon non-retention is another class of fishery inputs.

Through the month of March the NOF meetings shape inside fisheries (Washington Coastal terminal, Puget Sound marine and freshwater) for both Coho and Chinook Salmon for compliance with domestic and international requirements. The NOF planning informs the April meeting toward the development of the final set of ocean, inside, and terminal fisheries. The FRAM modeling results of the final adopted regulations for ocean fisheries are published in the Pre III Report, and submitted to the US Department of Commerce for approval under the MSA and confirmation of compliance with the US ESA and other domestic obligations. Inside fisheries are formalized by regional agreements by state and tribal managers. There is no ability to modify the regulations and agreements after they are adopted.

Throughout this process, the January post season, Pre I-III reports are provided to Canada as information. The Final April Coho FRAM run is also provided to Canada. It is the April model run that until recently has provided the information for post season assessment of (see Canadian section of “Timing of Domestic Planning” for potential exception).

3.2.3 US Inseason Management

Inseason changes to planned U.S fisheries are limited, but have been implemented under some specific conditions. When ocean area/fishery specific quotas are not being caught in an ocean area then part of the quota may be transferred to another ocean area/fishery, based upon FRAM estimates of neutral impacts to the limiting stock(s); this may include adjustments to bag limits, seasons, and/or MSF regulations. The preseason planned prosecution of some fisheries is dependent upon the results of test fisheries, i.e. the Fraser Panel Sockeye directed commercial fisheries. Emergency closures due to attaining or exceeding planned catch quotas or in response to indications of reduced abundance.

(*this would be updated with the most current year of information** ### US Management Units 2023 Exploitation Rate Constraints

For 2023, Puget Sound and Washington coast Coho Salmon constraints are as follows (Pacific Fishery Management Council 2023a):

Table 3.2: Fishery Management Plan (FMP)
FMP Stock Total Exploitation Rate Constraint Categorical Status
Skagit 35% Low
Stillaguamish 50% Normal
Snohomish 40% Low
Hood Canal 45% Low
Strait of Juan de Fuca 40% Low
Quillayute Fall 59%
Hoh 65%
Queets 65%
Grays Harbor 65%
Table 3.3: PST Southern Coho Management Plan
US Management Unit Total Exploitation Rate Constraint Categorical Status
Skagit 35% Moderate
Stillaguamish 50% Abundant
Snohomish 40% Moderate
Hood Canal 45% Moderate
Strait of Juan de Fuca 40% Moderate
Quillayute Fall 53% Abundant
Hoh 69% Abundant
Queets 53% Abundant
Grays Harbor 69% Abundant

FMP total constraint (Table 3.2) is preliminary. For Puget Sound stocks, the constraints and categorical status (Normal, Low, Critical) reflect application of Comprehensive Coho Agreement rules, as adopted in the FMP. For Washington Coast stocks, constraints represent MFMT. Note that under US v. Washington and Hoh v. Baldrige case law, the management objectives can differ from FMP objectives provided there is an annual agreement among the state and tribal comanagers; therefore, the used to report categorical status do not necessarily represent maximum allowable rates for these stocks.

(Table 3.3) constraint is Preliminary. For Puget Sound and Washington Coast management units, the constraints reflect application of the 2019 .

Under the , categories (Abundant, Moderate, Low) correspond to the general ranges depicted in paragraph 8(b)(iii) of the 2019 . For Washington Coast stocks, categorical status is determined by the associated with meeting the escapement goal (or the lower end of the escapement goal range). As Washington Coast stocks are managed to achieve agreed escapement goals, this also becomes an approximation of the maximum allowable rate unless the stock is in the “Low” status. In that case, an of up to 20% is allowed.

Grays Harbor constraints are based on projected natural area spawners (wild plus hatchery strays) and MSP escapement goal of 35,400. Exploitation rate constraint subject to change should comanagers agree to a modified escapement goal under US v. Washington and Hoh v. Baldrige case law.

Key considerations for Canadian fishery management for Coho Salmon in 2023 are expected to include:

  1. meeting domestic conservation obligations for Interior Fraser (including Thompson River) Coho Salmon;
  2. Coho Salmon harvests by First Nations fisheries;
  3. incidental impacts during commercial and First Nations fisheries directed at Chinook, chum, and especially Fraser Sockeye salmon which will see a dominant late run return in 2023 (Pacific Fishery Management Council 2023a).

The Canadian fishery regimes affecting Coho Salmon are expected to be driven by Canadian domestic allowable impacts on the Thompson River component of the Interior Fraser , Fraser Chinook Salmon concerns and Fraser Sockeye Salmon stocks of concern co-migrating with the late run. In years prior to 2014, Canadian fisheries were managed so as not to exceed a three percent maximum ER. In May 2014, Canada decided to permit up to a 16% ER on upper Fraser Coho Salmon in Canadian fisheries to allow for impacts in fisheries directed at a record Fraser Sockeye Salmon forecast. Since 2015, upper Fraser Coho Salmon in Canadian fisheries have been managed per low status limitations. The projected status of Canadian Coho Salmon management units in 2023 indicates continuing concerns for the condition of Interior Fraser Coho Salmon The Interior Fraser Coho Salmon is anticipated to remain in low abundance status, resulting in a requirement to constrain the total mortality fishery for 2023 Southern US fisheries to a maximum of 10.0%.

3.3 Canadian Fishery Planning Process

Annual Canadian fisheries are planned using a combination of two domestic models (marine fisheries and freshwater decay models) and tools focused upon Interior Fraser River (IFR) Coho Salmon The planning process starts early in the year. A draft IFMP is available for stakeholder comment in April, but the IFMP is not finalized until formally approved by the Fisheries Minister in June.

In the domestic process, initial planning scenarios are developed based on discussions with Fishery Managers, preliminary salmon outlook for stock status (prepared in November of previous year), effort expectation (targeted or incidental impact on IFR Coho Salmon) given constraints, and domestic allocation policy. Once stock abundance forecasts are available in March and timing and diversion forecasts for Fraser Sockeye are available in June, the final Salmon IFMP is submitted to the Minister for approval. The Canadian domestic model does not use Coho Salmon abundance forecasts directly, relying instead upon past relationships between fisheries’ effort and IFR , to estimate preseason projected for IFR. Depending on what species or fishery specific objectives are in place for the upcoming season, the domestic model is populated with anticipated effort based on trends in recent years and scaled to base period (1986–1997) effort. Multiple scenarios are run based on adjusting preliminary fishing plans (species, effort, month, gear, regulations) and results are reviewed by Fisheries Managers and evaluated for multiple objectives, in particular, meeting the preseason objectives for IFR CCoho Salmonoho.

3.3.1 Development of Canadian Preseason Coho FRAM Inputs

The US preseason Coho FRAM modeling requires Canadian inputs to complete the model for the US domestic planning and this also enables the pre to post season Coho FRAM evaluation of both Parties’ fisheries. The Canadian data used to inform Coho FRAM for annual US preseason planning and joint postseason evaluation are outlined below:

Preseason:

  • Stocks’ abundance forecasts, or;
  • Regional expected marine survival rates, based on indicator stocks;
  • FRAM fishery scalars by Coho FRAM time period from postseason analysis of a fishery plan similar to anticipated fishing patterns

Inseason:

  • FRAM fishery adjustments or significant deviations in expected abundance / catch

Postseason:

  • Stocks’ observed escapement, or;
  • Regional observed marine survival rates;
  • Fisheries’ observed catch by FRAM time period

Canadian FRAM Stock Abundance Inputs: US FRAM preseason modeling requires forecasts of Canadian stocks. Forecast development commences every year in early March, and is provided to US FRAM modelers in mid to late March for use at the second NOF meeting, prior to the April PFMC meeting.

To obtain these values Canadian forecast methodology uses the following information:

  1. Annual hatchery production
  2. Base Period FRAM natural production
  3. Base Period hatchery production
  4. Predicted marine survival
  5. Base Period marine survival
  6. Base Period FRAM stock abundance values

Estimates of freshwater production (smolt out-migrants) for hatchery produced Coho Salmon, by FRAM production region, are scaled to Base Period production. Next the annual expected regional marine survival (MS) is scaled to Base Period marine survival. Both ratios are applied to a stock’s Base Period Abundance to produce the annual adult abundance forecasts. To illustrate (by stock):

\[\text{Adult H Abundance} = \text{(Base Adult Abundance)}\frac{\text{(Annual H Smolts)}}{\text{(Base H Smolts)}} \frac{\text{(Expected MS)}}{\text{(Base MS)}}\]

Hatchery smolt data are obtained from the Canadian Salmon Enhancement Program. Where naturally produced smolt out-migrant estimates exists (2 of 14 Canadian production regions), the values are used. For the production regions where naturally produced smolt data are not available (the remaining 12 of 14 Canadian production regions), the default production starting values has been the same as the annual hatchery output for the same FRAM production region, which assumes similar smolt abundance trends between naturally produced and hatchery smolts occurs across time. (Jeromy comment - “Correct? If so, can we say in a sentence or two how reliable, or potentially unreliable this practice is going forward?”) As hatchery production has been reduced over time it has become necessary to find other means to obtain the surrogates for naturally produced smolt production.

Marine survival expectations have been based upon hatchery and wild indicator returns. As the number of Coho Salmon indicators has been reduced over time it has become necessary to use adjacent indicators to estimate marine survival for some and use hatchery indicators to estimate survival of naturally spawning Coho Salmon.

For IFR, where naturally produced smolt output is not available, the forecasted adult returns are used as inputs to Coho FRAM. This forecast is based on a naive model, usually an average of the previous three years estimated ocean adult abundance. However, the forecast may be “as observed last year” when it appears a longer term average is not appropriate; this was the case for the 2016 fishing year forecast. Several US 2016 forecasts also used the “as observed last year” approach due to the extremely poor returns in 2015 and the observations that those same poor environmental conditions existed for the smolts entering the ocean in 2015 (i.e., the 2016 adults).

Canadian FRAM Fishery Inputs:

Preseason FRAM’s anticipated fishery related mortality for Canadian Coho Salmon retention fisheries is modeled using Fishery Scalars (these Scalars essentially function as a harvest rate within the FRAM) taken from postseason Coho FRAM model runs with similar fishery plans and effort. For example, impacts of the Fraser River Sockeye directed fisheries may be estimated from 4 years previous. The Fraser River pink directed fishery impacts are estimated from the fisheries 2 year previous. The impacts from the Chinook troll fishery are based on a year with a similar Chinook harvest guidelines. The mortality associated with Coho Salmon non-retention regulation is another class of fishery inputs, also taken from previous postseason FRAM model runs under the assumption of similar fishery plans and effort, and similar Coho Salmon abundance levels.

3.3.2 Canadian Inseason Management

Canadian fishery planning process generally concludes in June, with the fisheries directed upon Fraser River salmon (Pinks, Sockeye, and Chum) driven by test fisheries. This later planning process can produce anticipated fishery impacts that diverge from the postseason Canadian fishery scalars used for the US domestic modeling the previous April. In such cases the April PFMC FRAM model run can be “updated” to evaluate both Parties compliance with the Coho Agreement.

3.4 Joint Canadian and US Postseason Evaluations

“Backwards Coho FRAM” is used to generate estimates of that are used to evaluate management performance relative to constraints set forth in the CoABM. Data required to populate FRAM are not available until one year after the fisheries were prosecuted, thus the 2021 postseason estimates were produced in February of 2023. The Backwards Coho FRAM is also employed to produce estimates of historic reported in this Periodic Report.

Backwards Coho FRAM requires estimated mortalities by fishery strata (uses the Base Period stock-fishery-time steps; terminal IFR fisheries have been incorporated recently) and available estimates of escapements to reconstruct annual cohort abundances and generate post-season estimates of . The escapement estimates for Coho FRAM stocks and catch information (catch, type of fishery –Mark Selective, Non-retention, Quota) for FRAM fisheries are compiled from various government agencies (USA: Federal, State and Tribal; Canada: Federal, and First Nations) and reviewed by the CoTC.

The Backwards Coho FRAM derives total cohort abundance of Coho FRAM stocks through an iterative process of estimating the set of stock abundance scalars that best explain observed escapements and reported catches. FRAM calculation of stock abundance scalars is the preferred method and occurs when escapement data are available (almost all US stocks). When escapement estimates are not available (almost all Canadian stocks), the stock abundance scalars are calculated externally and entered into FRAM; an estimate of “observed” marine survival has been used as a surrogate to recalculate Canadian stock abundances per the preseason method previously described. Consequently, FRAM’s iterative process of estimating a full set of stock abundance scalars is not possible and this has implications for backwards FRAM estimates of abundance for all stocks. Ideally total cohort abundance for each is derived by summing model estimated stock specific: pre-terminal catch, terminal catch, and escapement.

The Backwards Coho FRAM provides two estimates of cohort abundance, termed “Ocean age-3” (OA3) and “January age-3” (JA3). Ocean age-3 abundance includes escapement and fishery impacts. includes escapement, fishery impacts, and natural mortality. is the basis for stock status and is therefore the measure provided in the tables and figures in this report, and in the annual postseason evaluations.

These estimates of cohort abundance, catches and escapements are used to generate estimates of and determine status for post season reporting to the Southern Panel.

3.5 Overview of Coded Wire Tag Use

The use of the term indicator stock within this report does not imply a set list of agreed to indicator stocks. Instead, the CoTC assesses all available data for inclusion in the Mixed-Stock Model (MSM), cohort reconstructions, and other processes. With the base period spanning many years, it is beneficial if a stock is well tagged and well sampled over a long period of time. The coded-wire tag indicator stocks provide the primary data for predicting, monitoring, and modeling harvest impacts on individual Coho Salmon populations. The Joint Coho Technical Committee (CoTC) uses recoveries from the indicator stocks to reconstruct cohorts coastwide. While a few indicator tag groups are naturally-spawning fish, the vast majority consist of hatchery fish intended to represent each . Hatchery indicator stocks are selected on the basis of brood stock, rearing, and release strategies and are assumed to be surrogates for the naturally-spawning fish. The indicator program assumes that tagged and untagged fish experience similar trends in marine survival and similar exploitation patterns. Coastwide, approximately eight million juvenile Coho Salmon are coded-wire tagged annually (Nandor et al. 2010).

Some major changes in the indicator stock program have occurred since the was signed in 1985. One of the most notable changes is the mass marking of hatchery fish in the Pacific Northwest. For many years, an adipose fin clip was used as an external mark to identify fish (natural spawning or hatchery) with a . However, since brood year 1995 in the US and 1996 in Canada, the adipose fin clip has been used as a mass mark to identify hatchery-origin fish and no longer uniquely indicates a coded-wire-tagged fish. With the advent of mark-selective fishing, marked (adipose fin-clipped) and unmarked fish do not have the same patterns of exploitation, violating the fundamental assumption of the indicator tag program. These changes in marking and fishing have resulted in the development and use of double index tag (DIT) releases in the indicator tag programs. The group consists of two groups of hatchery fish, each 100% tagged with its own unique . The two groups are presumed to be identical, except that one tagged group is unmarked and the other group is marked with an adipose fin clip. In a MSF, catches of marked fish will be retained whereas catches of unmarked fish will be released. The difference in return rates to the hatchery reflects the difference in ocean ERs in selective fisheries. A group is recommended when the stock of interest is expected to be exploited by a mark-selective fishery (MSF). Unpaired (non-DIT) tag groups are either marked or unmarked and are considered single index tag (SIT) groups in this document.

To obtain unbiased estimates of fishery-specific impacts on individual stocks, a known proportion of both the catch and escapement must be sampled for throughout the migratory range of the stock and the proportion sampled must be adequate to produce a statistically reliable expansion of sampled Coho Salmon Mass marking creates the following two additional complexities for sampling of : (1) stocks are unmarked but contain ; and (2) marked fish do not necessarily contain . Therefore, all fish, not just marked fish (with an adipose fin-clip), must be sampled for . Detection of in unmarked fish requires electronic sampling using wands or tubes. Detection of in marked fish requires either field-based electronic sampling or collection of snouts for processing in the laboratory. For complete accounting, fish must be sampled throughout their range, in catch and escapement. Electronic sampling of both unmarked and marked Coho Salmon places an additional burden of time and expense on agencies

At present, the utility of the programs and the programs in general for Coho Salmon is reduced due to low tagging rates, insufficient representation (list which ones lack DITs - look at Table below), low recovery rates, and incomplete coastwide coverage of electronic sampling programs (Pacific Salmon Commission Coded Wire Tag Workgroup 2008). In addition, the programs: (1) currently provide overall differences in ocean – can’t discriminate individual fisheries; (2) have sample sizes that are generally small, so confidence limits are wide and estimates of differential impacts are imprecise; (3) are expensive and agencies are reluctant to fund tagging programs; and (4) unmarked fish are unavailable for harvest in MSFs.

Most in the US have indicator stocks and programs. However, some of the programs have been eliminated in recent years due to budgetary constraints. Canada has discontinued all of their Coho Salmon programs. The current Coho Salmon indicator stocks for each and the brood years with groups are listed below. The tag codes used in the Mixed-Stock-Model to develop the FRAM base period for catch years 1986-1997 are also listed below. All groups released within US to date are also listed below.

Table 3.4: Coded-wire-tag indicator stocks and brood years with single index tag (SIT) and groups for each Coho Salmon , beginning with brood year 1983. Indicator stocks are hatchery-produced Coho Salmon unless specified as “Wild” (Release data downloaded from RMIS 1-10-2023). SIT groups may be either marked or unmarked releases of Coho Salmon. groups are marked (adipose-fin clipped) and unmarked pairs of Coho Salmon.
Management Unit Indicator Stock Brood Yr SIT Brood Yr
Southern BC MUs
Lower Fraser Inch Creek Hatchery 83-95,14-19 96-13
Salmon River (Wild)1 84-99,01,03,05-07 NA
Chilliwack R. H. (Chilliwack R.) 83-95 96-02
Chehalis R. H. (Chehalis R.) 83-97 –
Interior Fraser Spius Cr. H. (Coldwater R.)2 84-94,96-98,03-19 99-02
Spius Cr. H. (Salmon R./TOMF)3 95-96,99,01-02,04-05,07,14,17-19 –
Spius Cr. H. (Spius Cr.)4 94-96,99-00 97-98
Spius Cr. H. (Eagle R.) 10-13,15-19 –
Chilliwack R. H. (Coldwater R.)5 16-19 –
Eagle R. H. (Salmon R.)6 83-93 –
Eagle R. H. (Eagle R.)7 83-93 –
Eagle R. H. (Perry R.)8 84-86 –
Dunn Cr. H. (Dunn Cr.)9 86-87,89-90,92,95,98-07 –
Dunn Cr. H. (Dunn Lake)10 84-91,94,97 –
Dunn Cr. H. (Lemieux Cr.)11 83-86,88,92-93,97-99,03,06-09 –
Dunn Cr. H. (Louis Cr.)12 88-94,97-07 –
Dunn Cr. H. (Ianson Ch.)13 88-91,94-95,00-02,04-05 –
Eagle River (Wild)14 00-03 NA
Lemieux Creek (Wild) 92-93 NA
Strait of Georgia Mainland Capilano R. H. 83-97,00 –
Lang Creek H. (Lang Cr.)15 87-91,95-96,08-09 –
Strait of Georgia Vancouver Island Quinsam R. H. 83-85,18-19 96-17
Big Qualicum R. H. 83-85,87-95,03-15,17-19 96-02
Goldstream R. H. 91-94,03-11 96-02
Puntledge R. H.16 83-97,99-02,09-10,19 –
Black Creek (Wild)17 83-17 NA
US Inside MUs
Skagit Marblemount H. (Skagit R.) 83-93 94-21
Baker River (Wild)18 83-97,00-22 NA
Stillaguamish19 Wallace R. H. (Skykomish R.) 83-95 96-21
Harvey Creek H. 91,07,14,16-20 –
Stillaguamish R. (Wild) 84-87 NA
Snohomish Wallace R. H. (Skykomish R.) 83-95 96-21
Bernie Gobin H. (Tulalip Cr.)20 83-21 –
Hood Canal Quilcene NFH 87-95 96-21
Quilcene Bay Sea Pens 88,90,93,95,02-11,13-14 96-01
Port Gamble Bay Pens 83-95,04-21 96-03
George Adams H. (Skokomish R.) 83-94,96 95,97-21
Big Beef Creek (Wild)21 83-21 NA
Strait of Juan de Fuca Lower Elwha H.22 85-94,12,15,18 95-11,13-14,16-17,09-20
Dungeness H. 83,86,89,91-94,05-08,18-20 –
Hoko Falls H. 18-20 –
Hoko and Salmon Creek (Wild) 84-87,08 NA
US Outside MUs
Quillayute Sol Duc H. 83-88,90-95 96-21
Various Tributaries (Wild)23 83-86,88-92
Hoh Chalaat Creek H. 84,86-89 –
Canyon Springs Pond 86-87 –
Sol Duc H. 85,87 –
Hoh River (Wild)24 83-87,03,05-12 NA
Queets Quinault Lake H. 83-84,90-92 –
Salmon R. Fish Culture 83,85-94 95-21
Queets/Clearwater wild25 83-11,13-20 NA
Grays Harbor Bingham Creek H. 83-94 95-21
Aberdeen Net Pens 88-90,92-94 –
Humptulips H. (Stevens Cr.) 83-94,06,10-12,19-20 95-96
Bingham Creek (Wild)26 83-20 NA
Stevens & Scatter Creek (Wild) 83-90,92-93 NA
Chehalis Upriver (Wild)27 83-97,00-20 NA
Skookumchuck H. 83,89,98,06-07,09, 11-12 98

3.5.1 Wild Stock Tagging programs

When developing the FRAM base period, the CoTC used wild indicator stocks to represent a when the data was available. The figures below summarize data currently reported in on coded-wire-tagged wild Coho Salmon smolts released within the . Most of the reported wild stock tagging has occurred in the Grays Harbor, and Queets ; followed by Strait of Georgia, Hood Canal, Skagit, and Lower Fraser . However, no wild stock tagging has been reported in the Lower Fraser since brood year 2007. Very little wild stock tagging has taken place in the remaining . Not all of the data depicted was used in the MSM and subsequent cohort reconstructions.

Figure 3.1

3.5.2 Hatchery Tagging Programs

When wild stock tagging was insufficient to represent a , the CoTC used hatchery indicator stocks to represent the . The figures below summarize all coded-wire-tagged hatchery Coho Salmon smolts released within the that are currently reported in . The total number of hatchery coded-wire-tagged fish released annually within the has varied over the years, with a low of approximately 1.4 million for brood year 2003 and a high of over 3 million for brood year 2020. With the advent of mass-marking in the 1990s, hatcheries began to release unmarked tag groups as early as brood year 1993. Most of these unmarked and tagged fish are part of a program.

Figure 3.2

Hatchery stock tagging has consistently occurred in every , with the exception of the Stillaguamish and the Hoh where very few hatchery fish are released. Double-index-tagging programs were implemented in all but the Stillaguamish and the Hoh ; however, programs currently exist only in the US .

Figure 3.3: Total number of tagged hatchery Coho Salmon smolts released by clip status for each over brood years 1983 through 2020 (data downloaded from RMIS 9-6-2023). “CWT_Unclipped_DIT” refer to tagged fish that are released with an intact adipose fin and are associated with a clipped release group. “CWT_Unclipped” are tagged fish that are unclipped but not associated with another tagged release group. These fish are often associated with new hatchery programs.

3.5.3 Total Hatchery Production

Reported hatchery production across the varies widely, from approximately 33,000 on average annually in the Stillaguamish MU , to an average of 5.4 million smolts released into the Strait of Georgia annually (data summarized over brood years 1983-2020). Prior to the advent of mass marking, some hatchery fish were released coded-wire-tagged with their adipose-fin clipped to identify it as a tagged fish, while the remaining fish were released unclipped and untagged. Beginning in 1995, programs began and their associated releases were mass-marked. Now, almost all of the hatchery production released into the in the US are mass-marked.

Figure 3.4: Total number of hatchery Coho Salmon smolts released by tag and clip status for each over brood years 1983 through 2020 (data downloaded from RMIS 9-6-2023). “CWT_Unclipped_DIT” refer to tagged fish that are released with an intact adipose fin and are associated with a clipped release group. “CWT_Unclipped” are tagged fish that are unclipped but not associated with another tagged release group. These fish are often associated with new hatchery programs.

4 Performance of Abundance Based Management Regime

In an attempt to evaluate the implementation of Abundance Based Management of Coho Salmon stocks of concern under the , summaries on abundance categories, exploitation, and forecast performance are provided below. Catch years summarized include 2004 through 2021 and abundance category and forecast performance summaries are limited to US and Interior Fraser River . A single year of post-season estimates of abundances, fishery exploitation, and escapement is first completed two years following each catch year. For example, an assessment of catch year 2022 will be completed in February of 2024. This report has been referred to as the Annual ER Report. This assessment is presented to the Southern Panel at the ’s Annual Meeting and the reports are posted on the CoTC’s and Southern Panel’s Sharepoint sites. These annual reports can also be found here. The best available data and the most current FRAM base period and Terminal Area Management Modules (TAMMs) are used to evaluate the catch year; however, data and the FRAM base period is updated or corrected on occasion. These corrections and additions are carried forward and are included in the post-season evaluations of below, sometimes resulting in changes from the annual reports in estimates of , escapement numbers, and Ocean Age-3 abundances.

4.1 Management Unit Post-season Abundances and Categories

Currently all of the except the Lower Fraser River and Georgia Strait have abundance break point criteria and associated for each abundance category. During catch years 2004 through 2021, were considered Abundant 43% of the time, Moderate 24% of the time, and the remaining 32% were in Low status. Interior Fraser was assigned Low status throughout the entire period assessed. US Inside were assigned an Abundant status less often (39% of the time) than US Outside (60%), while they were both assigned Low status nearly at equal rates (26 vs 24%). Over this 18 year period, it appears that Low status was more often assigned post-season beginning with catch year 2015, when 80% were in Low status. During catch years 2015 to present, 50% of the assignments were Low status. The US Strait of Juan de Fuca, Queets, and Grays Harbor were assigned Low status in three or more consecutive catch years beginning with catch year 2015. A summary of abundances and associated categories are provided in the following table and figure.

Table 4.1: Post-season estimates of Ocean Age-3 total abundances and their associated status categories [A = abundant, M = moderate, L= low] by for catch years 2004 through 2021. Management Units in the Abundant category have green highlighted cells, Moderate ones are not highlighted, and those in Low status are highlighted orange.
PSC_StockName 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
Canada
Lower Fraser 67,385 16,843 17,386 74,841 3,471 21,561 26,647 16,809 16,819 16,872 4,107 16,863 48,764 16,802 48,897 42,572 85,395 47,539 78,093
Interior Fraser 46,451 15,999 8,800 66,052 18,015 25,063 43,318 30,292 65,014 71,415 26,551 15,021 64,867 26,777 38,098 54,777 82,191 87,210 80,129
Strait of Georgia 306,419 48,138 51,218 220,554 15,361 65,107 80,449 26,576 28,866 57,344 42,333 12,750 12,356 12,636 45,757 32,727 109,574 140,232 128,444
US Inside
Skagit 169,157 [A] 52,362 [M] 11,518 [L] 84,423 [A] 35,458 [M] 87,600 [A] 64,581 [A] 78,116 [A] 139,009 [A] 150,661 [A] 51,696 [M] 15,512 [L] 44,736 [M] 22,278 [L] 36,911 [M] 27,499 [M] 41,468 [M] 111,989 [A] 124,042 [A]
Stillaguamish 66,035 [A] 30,687 [A] 10,804 [M] 51,708 [A] 16,874 [M] 30,871 [A] 16,753 [M] 61,324 [A] 60,518 [A] 78,066 [A] 49,138 [A] 5,455 [L] 15,619 [M] 6,918 [L] 30,885 [A] 16,165 [M] 24,654 [A] 42,702 [A] 59,711 [A]
Snohomish 289,505 [A] 133,924 [A] 94,754 [M] 157,393 [A] 49,412 [L] 134,407 [A] 54,375 [M] 137,411 [A] 175,650 [A] 175,980 [A] 66,635 [M] 27,593 [L] 54,137 [M] 23,190 [L] 77,581 [M] 48,671 [L] 47,717 [L] 109,873 [M] 93,201 [M]
Hood Canal 199,071 [A] 54,731 [A] 51,153 [A] 88,814 [A] 40,827 [M] 58,159 [A] 14,526 [L] 56,824 [A] 125,109 [A] 37,882 [M] 69,596 [A] 63,699 [A] 31,828 [M] 34,963 [M] 18,696 [L] 14,666 [L] 23,616 [M] 45,719 [A] 20,007 [M]
US Strait JDF 21,816 [M] 10,933 [L] 4,184 [L] 8,613 [L] 3,487 [L] 16,743 [M] 20,053 [M] 11,715 [M] 12,534 [M] 9,800 [L] 13,811 [M] 4,711 [L] 8,692 [L] 5,856 [L] 5,939 [L] 5,258 [L] 9,200 [L] 22,440 [M] 18,396 [M]
US Outside
Quillayute 14,090 [A] 20,820 [A] 9,455 [M] 10,672 [A] 10,018 [M] 12,475 [A] 17,083 [A] 13,348 [A] 12,815 [A] 15,788 [A] 17,258 [A] 4,800 [L] 11,696 [A] 12,931 [A] 8,666 [M] 10,905 [A] 9,107 [M] 11,578 [A] 16,266 [A]
Hoh 5,366 [A] 8,217 [A] 2,064 [L] 4,904 [A] 3,970 [A] 12,023 [A] 11,375 [A] 12,978 [A] 8,089 [A] 9,152 [A] 9,136 [A] 2,928 [M] 5,417 [A] 6,044 [A] 3,739 [A] 5,157 [A] 5,386 [A] 7,790 [A] 11,686 [A]
Queets 13,445 [A] 12,149 [A] 8,695 [M] 6,828 [L] 7,335 [M] 18,733 [A] 20,070 [A] 15,170 [A] 9,194 [M] 9,932 [A] 12,903 [A] 2,748 [L] 6,070 [L] 6,797 [L] 3,446 [L] 3,944 [L] 5,126 [L] 5,261 [L] 17,811 [A]
Grays Harbor 68,872 [A] 73,009 [A] 26,881 [L] 34,718 [L] 51,708 [M] 113,275 [A] 117,353 [A] 86,208 [A] 103,923 [A] 80,323 [A] 152,912 [A] 31,714 [L] 35,331 [L] 37,344 [L] 60,777 [A] 50,994 [M] 31,581 [L] 77,315 [A] 79,356 [A]

Estimated post-season ocean age-3 cohort abundances for the are depicted below. Abundances for BC and US Inside tend to be synchronous, with above- or below-average abundances occurring in the same years (e.g., high in 2001, low in 2006). Outside are less synchronous and years with high abundances for Grays Harbor don’t necessarily correspond to high abundances for other .

Figure 4.1: Estimated Post-season Ocean Age-3 Abundances of BC Coho Salmon Management Units
Figure 4.2: Estimated Post-season Ocean Age-3 Abundances of US Inside Coho Salmon Management Units
Figure 4.3: Estimated Post-season Ocean Age-3 Abundances of US Outside Coho Salmon Management Units
Figure 4.4: Summary of the number of in each abundance category each year, based on post-season assessments of Ocean Age-3 Abundances.

4.1.1 Fishery Exploitaion Rate Overview

Recent catch years with the highest estimated average over all include catch years 2014 (42%) and 2015 (43%), while the experienced the lowest , on average, in catch years 2016 (16%) and 2021 (14%). Estimates of post-season total by for catch years 2011 through 2021 are listed in the table below, while average by and FRAM fishery are depicted in the figures below.

Canadian

Over catch years 2011 through 2021, the Canadian experienced varying from a low of 6.5% by the Strait of Georgia in 2021 to a high of 56.8% by the Lower Fraser in 2014. The averaged 21.5% over all years for the Lower Fraser River , followed by the Interior Fraser at 16.9%, and Strait of Georgia at 16.8%.

US Inside

US Inside were the lowest for the US Strait of Juan de Fuca at 3.0% in 2016 and were the highest at 68.3% for the Hood Canal in 2014. The averaged 48.5% over all years for the Hood Canal , followed by the Skagit at 39.6%, Snohomish at 23.8%, Stillaguamish at 21.3%, and US Strait of Juan de Fuca at 10.2%.

US Outside

Over catch years 2011 through 2021, the US Outdside also experienced a large range of , from a low of 3.8% by the Quillayute in 2021 to a high of 69.0% by the Hoh in 2013. The averaged 41.7% over all years for the Hoh , followed by the Quillayute at 36.6%, the Queets at 34.8%, the Grays Harbor at 34.6%, and Strait of Georgia at 16.8%.

(ToDo - need to move Canadian MUs to top of table and bold the values when the ERs exceeded the caps)

Total exploitation rates by , catch years 2011 through 2021.
PSC_StockName 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
US Inside
Skagit 43.8% 33.3% 43.1% 52.0% 62.7% 19.9% 9.4% 48.4% 48.2% 42.6% 32.6% 25.6%
Stillaguamish 18.5% 25.4% 22.6% 27.1% 46.6% 16.5% 11.8% 22.5% 20.3% 12.6% 10.6% 9.9%
Snohomish 18.9% 25.6% 28.5% 30.6% 53.6% 18.5% 21.5% 25.1% 17.2% 10.6% 11.2% 8.1%
Hood Canal 57.1% 58.6% 57.7% 68.3% 58.7% 40.1% 35.6% 57.3% 46.1% 28.7% 24.8% 54.1%
US Strait JDF 8.4% 12.1% 13.7% 16.8% 18.1% 3.0% 5.6% 7.9% 12.0% 7.1% 7.1% 7.7%
US Outside
Quillayute 39.6% 54.4% 55.3% 57.1% 47.1% 18.4% 42.3% 29.7% 37.2% 17.2% 3.7% 18.8%
Hoh 39.2% 50.8% 69.0% 51.8% 39.2% 7.9% 42.9% 34.4% 56.6% 49.2% 17.9% 30.4%
Queets 40.1% 49.8% 38.2% 42.2% 36.3% 24.9% 22.9% 35.9% 41.3% 41.8% 9.7% 30.1%
Grays Harbor 38.9% 47.1% 44.4% 44.9% 48.5% 11.5% 32.3% 21.9% 39.6% 28.6% 22.4% 28.8%
Canada
Lower Fraser 23.6% 17.9% 27.6% 56.8% 42.0% 12.4% 12.4% 12.0% 14.0% 9.6% 7.7% 10.3%
Interior Fraser 14.3% 14.5% 20.6% 35.3% 24.0% 9.2% 9.7% 15.3% 20.0% 13.4% 9.5% 12.4%
Strait of Georgia 16.5% 15.9% 25.8% 32.1% 30.1% 9.9% 9.7% 14.3% 16.2% 7.4% 6.5% 8.8%

4.1.2 Forecast Performance

Forecasts are integral to Coho Salmon management in the Pacific Northwest. These forecasts, as described earlier, are used in pre-season assessments to determine allowable fishing mortality on stocks of concern. In the absence of in-season management controls, forecasts that are too high may yield higher than agreed to exploitation of management units of concern. Forecasts that are too low may yield losses in fishing opportunities.

Pre-season forecasts of all of the over the catch years 2004 through 2021 have often (63%) been within the abundance based categories assigned post-season. Forecasts were too high 24% of the time and too low 13% of the time. The forecasts for catch years 2005 and 2011 were very good, resulting in no change in abundance categories from pre- to post-season estimates of abundance. Forecasts were poor for catch years 2006, 2015, and 2021, where less than 50% of the forecasted were within the abundance category assigned post-season. There does not appear to be an obvious trend in forecast performance of abundance categories across all with available forecasts over catch years 2004 through 2021.

Figure 4.5: Comparison of pre-season abundance to post-season abundance based on whether the abundance category was correctly predicted, for all MUs.

Pre-season forecasts for the five US Inside over catch years 2004 through 2021 were within the abundance based categories assigned post-season 54% of the time, too high 28% of the time, and too low 18% of the time. Forecasting was poor for catch years 2006 and 2010, where only 1 was forecasted within the abundance category assigned post-season. In addition, only two of the five forecasted were within the abundance category assigned post-season in each of eight additional catch years. Forecasts were more often correct (72% of the years) for the Hood Canal , followed by the US Strait of Juan de Fuca (56%), Skagit and Stillaguamish (50%), and least correct for the Snohomish (44% of the years).

Figure 4.6: Comparison of pre-season abundance to post-season abundance based on whether the abundance category was correctly predicted, for US Inside MUs.

Forecasts for the US Outside performed better, on average, than the US Inside forecasts of abundance categories. Pre-season forecasts for the four US Outside over catch years 2004 through 2021 were within the abundance based categories assigned post-season 64% of the time, too high 25% of the time, and too low 11% of the time. The forecasts for catch years 2005, 2009-2011, and 2014 were very good, resulting in no change in abundance categories from pre- to post-season estimates of abundance. Forecasting performance was poor for catch years 2006, 2015, and 2021. Forecasts were more often correct (72% of the years) for the Hoh and Quillayute , followed by the Queets (61%), and least correct for the Grays Harbor (50% of the years).

Figure 4.7: Comparison of pre-season abundance to post-season abundance based on whether the abundance category was correctly predicted, for US Outside MUs.

4.2 Management Unit Descriptions and Assessment of Performance

4.2.1 Skagit

This description was prepared by U.S. members of the Coho Technical Committee.

4.2.1.1 Biological and Geographic Description

The Skagit is one of the US Inside (refer to figure of inside MUs). This is comprised of all wild Coho Salmon that originate from the Skagit Basin. The Skagit River consists of Coho Salmon in the Skagit River Basin and its major tributaries, the Baker, Sauk-Suiattle, and Cascade Rivers (MU Figure - fix Oak Harbar spelling). The Skagit River is located in Northern Puget Sound midway between Seattle, Washington and Vancouver, British Columbia. The Skagit Basin drains the northern Cascade Mountains, flowing westward to Puget Sound and enters Puget Sound southwest of the city of Mt Vernon after splitting into to two similar-sized channels several miles above tidewater (Haymes 2008). The basin area accessible to anadromous salmonids downstream of the Skagit River reservoir system is 1,918 mi2 [4,968 km2] (Volkhardt et al. 2007). It drains Puget Sound’s largest basin, with an area of nearly 4,000 mi2 and an average discharge of over 16,000 cfs (one-third of the freshwater inflow to Puget Sound). It is the second largest river system in the state of Washington in terms of annual discharge, after the Columbia River. The Skagit River contains 162 miles of mainstem river, with its origin in the Coveole Mountains of British Columbia.

The mainstem Skagit and Sauk rivers have two periods of peak flow, first during winter rain and snowmelt events, and the second during peak snow runoff in spring and early summer. The smaller tributaries are largely rain-fed, and have peak flow events during the winter rain season. Average annual rainfall is 35 inches [89 cm] per year at Mt. Vernon in the lower valley, increasing to up to 180 inches [457 cm] per year in the upper basin. Three large reservoirs in the upper Skagit River drainage (the first located at river mile (RM) 96.6 [KM 155.5] from the estuary) and two in the Baker River drainage provide flood control and hydroelectric generation. Upriver fish passage is only provided at the Baker Reservoir system, via a trap and haul system located at a diversion dam 0.3 miles [0.5 km] upstream of the Baker River confluence with the Skagit River at a diversion dam. Puget Sound Energy completed construction of this new, enhanced fish trap below Lower Baker Dam to capture migrating adult salmon for upstream transport around both Baker River dams. Construction on a juvenile salmon downstream fish trap, a floating surface collector, was completed in 2008 behind the upper Baker River Dam. A similar fish trap is under construction on Lake Shannon, below Lower Baker Dam.

In the 3,910 mi2 [10,127 km2] watershed, 19% is owned by private and Washington State entities, 24% is managed by the Mt Baker-Snoqualmie National Forest, 44% by the North Cascade National Park and Recreation Area, and 13% is located within British Columbia (Beechie et al. 1994). The Skagit Bay estuary is partially enclosed by Whidbey Island to the west and Camano Island to the south. Relatively minimal development is located directly adjacent to the estuary in most areas. The WDFW Skagit Wildlife Area fronts the southeastern edge of Skagit Bay at the river mouth, and the northeastern end of the bay is bounded by the Swinomish Indian Reservation.

Recreational, conservation, and commercial forest activities are prevalent in the mid- and upper basin reaches. The lower and mid-basin areas have significant habitat impacts from agricultural and residential/commercial development in the floodplain and surrounding uplands. Extensive flood control structures degrade the salmonid habitat in the floodplain and estuary, with over 60 miles [97 km] of historically available slough and tributary habitat lost from the construction of flood control structures alone. The rapidly growing city of Mount Vernon, located adjacent to the Skagit River at RM 11 [KM 18] from the estuary, is the largest urban center in the . Other moderate-sized communities located in the are Burlington and Sedro Woolley, also located in the Skagit River floodplain a few miles upstream of Mt Vernon. Human population densities decline upstream of Sedro Woolley, though smaller, residentially-oriented communities are scattered along the Skagit mainstem upstream to the town of Newhalem at RM 96 (KM 154]. The Sauk River valley has only one significant population center, Darrington, located at RM 22 [KM 35] from the Sauk/Skagit confluence, though residential development and some agricultural activity is scattered along the valley floor.

In the upper reaches of the Skagit watershed, the land is primarily forested and moderately steep gradient; the main land use in this area is forestry. Below the confluence with the Sauk, the valley broadens and flattens and is used extensively for agriculture.

A major limiting factor on Skagit Coho Salmon production is floodplain diking and hydromodification, which has reduced distributary slough area by about 64%, and off-channel slough area by about 45% (Beechie et al. 1994). This has reduced Coho Salmon smolt production by an estimated 300,000 smolts per year (Puget Sound Salmon Stock Review Group 1992). Improperly placed culverts have also restricted access to a significant amount of tributary spawning and rearing habitat. Poor water quality and abnormally high flows, which are caused by agricultural practices and clear-cutting, have reduced production in much of the lower basin (Beamer et al. (2000)).

There are currently two recognized Coho Salmon populations in the system, Baker and Skagit (WDFW and WWTIT 1994). The Baker run historically entered the system somewhat earlier than the Skagit run, but the two populations are nonetheless managed as a single MU because: 1) there is considerable overlap in run timing, which would make it difficult to manage for separate escapement goals for each run; and 2) hatchery practices have so crossbred Baker and Skagit Coho Salmon that it is questionable whether a genetically separate Baker run population exists anymore (WDFW and WWTIT 1994).

Skagit Coho Salmon belong to the larger Puget Sound/Strait of Georgia Coho Salmon evolutionarily significant unit (ESU) (Weitkamp et al. 1995). This ESU is currently a species of concern under the US Endangered Species Act (Ford 2011).

Numerous salmon hatchery facilities exist within the Skagit Basin, including small and large operations (MU figure). Below is a list of the larger Coho Salmon programs that are operating in the Skagit Basin.

  • The WDFW operates the Marblemount Hatchery on the Cascade River at RM 0.5 at the confluence with Clark Creek (MU figure). The Cascade River is a tributary to the Skagit River at RM 78. Marblemount Hatchery was constructed in 1946 and currently rears Skagit spring, summer, and fall Chinook Salmon; Skagit Coho Salmon; Skagit Steelhead; and Ross Lake Rainbow Trout (Washington Department of Fish and Wildlife 2003a). The Coho Salmon program is operated as an isolated harvest program with an annual production goal of 250,000 smolts to be released on station, 45,000 fish to net pen projects (Oak Harbor and Roche Harbor), 100,000 fish to Skagit System Coop (Swinomish Tribe), and 13,000 eggs to educational and volunteer cooperatives. Its current purpose is to provide harvest opportunity for non-tribal sport and commercial fishers and tribal fishers (Washington Department of Fish and Wildlife 2003a). This program collects adult broodstock on-site, and has egg incubation and rearing facilities. Within the Skagit approximately 77% of the total hatchery fish reported to have been released for brood years 1983 through 2020 has been from the Marblemount Hatchery.

  • A fish culture facility has also been in operation on the Baker River since the early 1970s, producing Sockeye, Rainbow Trout, and Coho Salmon (WDFW_and_PSE_2003?). Puget Sound Energy completed construction in 2010 of a new hatchery on the Baker River near the upper Baker Dam. Coho Salmon fry from this program are transported to net pens on Lake Shannon and they are later released as smolts into the Baker River and both reservoirs. This Coho Salmon program is operated as an integrated harvest and research program with an annual goal of releasing 60,000 smolts. The purpose of this program is to supply experimental and research smolts for gulper efficiency testing, serve as an indicator stock for wild Skagit Coho Salmon, and supplement natural production in the basin.

  • Coho Salmon are also reared in net pens within the Oak Harbor Marina (Washington Department of Fish and Wildlife 2003b). This Coho Salmon program is a marine net pen program operated by WDFW and local sport angling groups and usually receives stock from the Marblemount Hatchery and is operated as an isolated program with an annual goal of releasing 30,000 smolts. The purpose of this program is to provide harvest opportunity for sport and commercial fishers.

4.2.1.2 Management Framework

Objectives

Under the Comprehensive Coho Management Plan, Skagit River wild Coho Salmon is the primary (or key) and hatchery production are either secondary (Swinomish Channel, Oak Harbor Pens) or auxiliary (Marblemount Hatchery, Baker River Hatchery) (Comprehensive Coho Workgroup 1998). Under this plan, primary are controlling units in the sense that predefined management actions will be undertaken under specified abundance conditions, auxiliary are those managed to meet or exceed a minimum escapement, and secondary units are passively managed in mixed stock fisheries. Therefore, Skagit River Coho Salmon are managed for natural (wild) production. * JJ question - So, hatchery fish spawning in the river count towards the wild escapement goal, or not? This type of specificity should be spelled out for each MU very clearly.* While there is hatchery production within the system, fisheries are constrained to meet the natural escapement objectives. Thus, there are frequently significant surplus returns to the Marblemount Hatchery on the Cascade River. There have been fisheries in the Skagit terminal area targeted at hatchery Coho Salmon, but these have been sporadic, and have been confined to small areas (e.g., the creek immediately downstream of the hatchery, Swinomish Channel from 1986–1991, and Oak Harbor from 1994–1996).

Skagit Coho Salmon are also a primary for Puget Sound under the FMP (Pacific Fishery Management Council 2013). Other primary in this region are Strait of Juan de Fuca, Hood Canal, Snohomish, Stillaguamish, and South Puget Sound (hatchery) Coho Salmon (Pacific Fishery Management Council 2013). The ’s conservation objectives for these are based on the Puget Sound Salmon Management Plan, which includes management objectives and long-term goals for these stocks as developed by representatives from federal, state, and tribal agencies.

In Puget Sound, conservation objectives for specific stocks are based on either maximum sustainable production for stocks managed primarily for natural production or on hatchery escapement needs for stocks managed for artificial production. The original conservation objectives were developed by a State/Tribal Management Plan Development Team following the Boldt Decision (384 F. Supp. 312 [W.D. Wash. 1974]) with the goal for natural spawning stocks defined as “the adult spawning population that will, on the average, maximize biomass of juvenile outmigrants subsequent to incubation and freshwater rearing under average environmental conditions”. The method used to develop the objectives was based on assessment of the quantity and quality of rearing habitat and the number of adult spawners required to fully seed the habitat. Some objectives have subsequently been modified by the US District Court Fisheries Advisory Board and later determinations of the WDFW/Tribal Technical Committee. However, annual natural management objectives may be adopted by the and authorized by NMFS which vary from the fisheries management plan (FMP) conservation objectives if agreed to by WDFW and the treaty Indian tribes under the provisions of US versus Washington (384 F. Supp. 312 [W.D. Wash. 1974]) and subsequent US District Court orders.

In 2009, the adopted annual management objectives for Puget Sound Coho Salmon as recommended by WDFW and tribal co-managers under provisions of US versus Washington. The annual objectives were based on the categorical status and associated maximum limits. The formally adopted management objectives for Puget Sound Coho Salmon in November 2009, which were consistent with objectives, and in 2010 these new objectives replaced the longstanding FMP spawning escapement objectives.

The current / ceilings for the Skagit natural Coho Salmon population are provided in the table below. The current corresponding ocean abundance reference points are 62,500 and 22,857 adult Coho Salmon (Pacific Fishery Management Council 2013). Prior to adoption of -based management for this in domestic and international management processes, natural Skagit River origin Coho Salmon were managed for a fixed escapement goal of 30,000. This goal was derived from a freshwater juvenile carrying capacity model (Zillges 1977).

Table 4.2: Current Skagit ocean abundance reference breakpoints and maximum total by and status categories.
Status(PSC/) Ocean Abundance
Reference Breakpoint		 Total Exploitation Rate
Low/Critical < 22,858 Up to 20%
Moderate/Low 22,858 – 62,500 21% – 35%
Abundant/Normal > 62,500 36% – 60%
Stock Assessment
Indicator Stocks

The Skagit MU has both hatchery and wild Coho Salmon indicator stock programs. Wild Yearling Coho Salmon are captured, coded-wire-tagged, and released within the Skagit Basin (Litz 2023). These releases are currently used as a marine survival rate indicator for the wild stock. The Skagit hatchery stock releases from Marblemount Hatchery and the tagged wild stock releases are used as indicator stocks. Coho Salmon released from Marblemount Hatchery have been double index tagged starting with brood year 1994.

Coded wire tag recovery-based survival and data are available for the Marblemount Hatchery and wild Coho Salmon tagging programs (Haymes 2008). The wild stock program (AKA Baker River program) began with broodyear 1983 and its purpose is to supply experimental and research smolts for gulper efficiency testing, serve as an indicator stock for wild Skagit Coho Salmon, and supplement natural production in the basin (WDFW_and_PSE_2003?). An average of 39,000 Baker Lake wild smolts were captured, coded-wire tagged, and adipose fin clipped annually ((fig_wild_stock_tagging_skagit?)) for broodyears 1983 through 1995. Beginning with brood year 1996, an average of 20,000 fish have been captured and released annually with a and their fins intact. The Marblemount Hatchery Coho Salmon program has been in existence for over 64 years and its purpose is to provide harvest opportunity (Washington Department of Fish and Wildlife 2003a). The hatchery indicator program is currently a program (differentially tagged fish released with or without adipose clips) with a goal of releasing 45,000 tagged fish of each group, one with an adipose fin clip and one without (Washington Department of Fish and Wildlife 2003a) ((fig_hatch_stock_releases_mu_cwt_only_skagit?)). Annual tagged and adipose fin clipped releases prior to the implementation of the program were 68,000 on average (Table 9.1). The program began with brood year 1994 and an average of 70,000 tagged and clipped fish have been released annually, while tagged and unclipped fish have averaged approximately 44,000 annually. values for the non-ad clipped+ Coho Salmon provide a surrogate measure of exploitation for natural origin Coho Salmon from this . There is no regular sampling of the freshwater sport fisheries in the , which results in some negative bias in tag recoveries. Double index tag groups released for the Skagit are provided below.

ToDo: Fix the figure references in above paragraph

Number of wild fish caught, tagged, and released by clip status, within the Skagit MU over brood years 1983 through 2020.

Total number of coded-wire-tagged hatchery Coho Salmon released, by clip status, within the Skagit MU for brood years 1983 through 2020.
Forecast Methods

Since 1996, WDFW and tribal biologists have developed forecasts of wild Coho Salmon run size for all primary and most secondary in Puget Sound and the Washington coast (Zimmerman 2013). These annual forecasts are described in the ’s Preseason Forecast I document available each February [e.g., Pacific Fishery Management Council (2013); www.pcouncil.org]. These forecasts rely on estimates of wild Coho Salmon production (i.e., smolts) paired with estimates of marine survival. Wild Coho Salmon production estimates for each of the primary and secondary in Puget Sound were derived from results of juvenile trapping studies conducted in the Skagit, Stillaguamish, Snohomish, Green, Nisqually, and Deschutes rivers as well as in tributaries to Lake Washington and Hood Canal. Analyses of these long-term data sets have demonstrated that wild Coho Salmon smolt production is limited by a combination of factors including seeding levels (i.e., escapement), environmental effects (flows, marine derived nutrients), and habitat degradation (Zimmerman 2012).

Estimates of wild Coho Salmon production in the Skagit Basin are based on catch of wild Coho Salmon smolts in a juvenile trapping program on the lower mainstem Skagit River (Litz 2023). WDFW operates a scoop-and-screw trap combination in the lower Skagit River mainstem, located at RM 17 from the river mouth. Trapping began in 1990 and the juvenile trap is calibrated using recaptures of wild yearling Coho marked and released from an upstream tributary (Mannser Creek, RM 35). Coho Salmon abundance is calculated using a Petersen estimator with Chapman modification (Seber 1973; Volkhardt et al. 2007). Estimated smolt production has been quite consistent in the Skagit , averaging 1.1 million smolts annually from 1990 to 2022 ((fig_smolts_skagit?)). Smolt production has varied from a low of 426,963 in 2008 to a high of 1,885,000 in 2002 and has exceeded 1,000,000 smolts in 20 of the last 33 years. Freshwater productivity (smolts/female) during this period was a function of Coho spawner abundance. The smolt-spawner function derived based on Skagit Coho Salmon estimates is comparable to systems with census counts, lending further credibility to the Skagit juvenile and adult estimates.

Figure 4.8: Estimated number of Skagit MU wild Coho Salmon smolts outmigrants, years 1990 through 2022

Marine survival rates of wild Coho Salmon stocks have been estimated using wild indicator stocks in four geographic regions of Puget Sound: Big Beef Creek (within the Hood Canal MU); Deschutes River; South Fork Skykomish River; and Baker River (within the Skagit MU) (Zimmerman 2012). These populations are assumed to be representative of the different Puget Sound regions. In the Baker River, a tributary to the Skagit River, marine survival of Coho Salmon smolts has averaged 7.8% (range of 1.1% and 13.9%) over 29 brood years (1989–1997, 2000–2020), with a high of 13.9% for brood year 1987 and a low of 1.1% for brood year 2003. High survival (>11.5%) for brood years 2020 through 2022 is encouraging.

ToDo: create this image from the excel file: Skagit Marine Survival Rates

Estimated marine survival rates for Baker River Coho Salmon, (data provided by M. Litz, WDFW).

Most Recent Abundance Forecast and Methods This information is available in the ’s 2024 Preseason Report 1 (Pacific Fishery Management Council 2024c) and (Litz 2024).

The 2024 Skagit abundance forecast is 63,430, resulting in a classification of the stock abundance as “Abundant” under the 2019 and “Normal” under the . This results in an allowable total of no more than 60%.

This forecast was based on a prediction of total (Baker wild + Skagit wild) smolt to ocean age-3 survival. Note that this forecast is not based on the Baker River wild indicator survival. Instead, the total survival was calculated assuming that the ratio of total wild terminal run size to Baker River wild indicator run size is equal to the ratio of total pre-terminal wild catch to Baker River pre-terminal wild catch. Using that ratio, total wild run size was calculated utilizing pieces of the Skagit co-manager run reconstruction, , and . Due to the large uncertainty surrounding how ocean conditions would influence the survival of 2023 outmigrants, ’s alternative Coho Salmon forecast for Baker River wild indicator survival in the report ‘2024 Wild Coho Forecasts for Puget Sound, Washington Coast, and Lower Columbia’ relying on generalized additive model methodology was also incorporated into the final agreed upon forecast (Litz 2024).

Escapement Monitoring

Escapements to the Baker system are counted at the Baker trap. Hatchery fish are distinguished by ad-clips. Wild fish returning to the Baker, including those that carry , are not ad-clipped.

Natural Coho Salmon escapement estimation efforts in the Skagit have a long and problematic history and are a textbook example of the challenges of estimating Coho Salmon escapements to large watersheds (Haymes 2008). An early effort at estimating a basin-total Coho Salmon escapement to this was a 1961 Washington Department of Fisheries (WDF, now Washington Department of Fish and Wildlife, or WDFW) mark-recapture (M/R) escapement study. This study focused on deriving a Pink Salmon (O. gorbuscha) escapement estimate for that year, but also tagged returning adult Coho Salmon to develop a Coho Salmon escapement estimate from spawning ground tag recoveries (Stockley 1963). The Coho Salmon escapement estimate derived from this study (116,726) was confounded by low numbers of tagged Coho Salmon adults (289), limited tag recovery effort during the Coho Salmon spawning season, low numbers of tags recovered, and poor distribution of the tag recoveries (68 tags, of which 60 came from the Baker Lake adult trap, a drainage which accounts for a small fraction of the total natural Coho Salmon escapement to this ).

A more serious attempt to directly estimate natural Coho escapements in the northern Puget Sound river basins was made in 1976 and 1977 when two major M/R escapement studies were conducted to estimate the Coho and Chum Salmon escapements to these rivers (Eames et al. 1983). The results of these studies provided the information needed for implementation of a Base-Year Index escapement estimation approach for the rivers in the Puget Sound region. The Base-Year Index escapement estimation approach was selected by the Washington Department of Fisheries (WDF) for annual estimation of Chum, Pink, and Coho Salmon escapements for these river basins because the method utilized visual spawning survey observations in lieu of expensive annual M/R studies.

Questions soon arose about the accuracy of escapement estimates produced by the index-base year approach, however. A new M/R escapement study for the Skagit River was attempted by the treaty tribes in 1984 to generate a comparative escapement estimate, but an inadequate number of Coho Salmon were tagged to develop an estimate (Hayman and Beamer 1987). An alternative approach was also examined for the 1984 escapement using the ratio of wild to hatchery-origin Coho Salmon observed in the lower river test fisheries multiplied by the hatchery return to Marblemount Hatchery to estimate the wild escapement (a “reverse form” Petersen M/R-type estimate), which produced an estimate considerably higher than the Base-Year Index approach for that year, 100,000 vs. 35,600 (Hayman and Beamer 1987).

In the 1986 to 1990 time period, M/R-based natural Coho Salmon escapement estimation studies were again conducted in the Skagit Basin by the treaty tribes (Conrad et al. 1997, 1998a, 1998b, 1998c). Returning adult Coho Salmon were captured by beach seine in the lower river, jaw tagged, and the tags subsequently recovered in in-river test fisheries, hatchery, dam or tributary fish traps, or spawning ground surveys. Peterson and Darroch analyses were conducted on the jaw tag recoveries to estimate the escapement in each of these years and compared against Index Spawning Redd-based estimates, estimates based on the proportional contribution of hatchery origin Coho Salmon to the total escapement, and the traditional Base-Year Index method that were conducted in the same years. The M/R-based escapement estimates were up to 575% higher than the Base-Year Index estimates for the same time period. The estimates based on proportional contribution of hatchery Coho Salmon to the Skagit escapement conducted in the same time period were also considerably higher than the Base-Year Index approach. These results were also supported by the observed smolt production estimates in this same time period which indicated the escapement estimates generated by the Base-Year Index approach were too low to produce the observed juvenile production.

In the 1990s another escapement estimation approach was developed for Skagit Coho Salmon that uses the observed marine survival rate of tagged Baker Lake origin wild Coho Salmon for each year multiplied by the parent year Skagit basin smolt out-migration to produce an estimate of total adult recruitment, which is multiplied by (1 - the Baker Wild -recovery fishery ) to generate the escapement estimates (Seiler et al. 1995). These estimates were also typically considerably higher than the Base-Year Index estimates.

There are a number of reasons for the differences observed in the escapement estimates derived by the various methods discussed above. The Base-Year Index escapement formula for the Skagit has an inherent negative bias due to a decision made by WDF management biologists following completion of the 1977 mark-recapture escapement study to select a value approaching the lower bound of the 95% confidence interval from the M/R study results as the “base year” escapement estimate [WDF_1985]. The 29,200 value that was selected by the WDF managers is considerably lower than the M/R study point estimate of 43,000, which has a 95% confidence interval (CI) of 25,211–148,464. This decision was based on concern about the limited number of marks recovered in the M/R study, and the subsequent possibility of positive bias in the M/R-based estimate. Further uncertainty in the 1977 M/R estimate was highlighted by a re-analysis of the 1977 M/R study data by the Northwest Indian Fisheries Commission (NWIFC) that produced a point estimate of 110,758, with a 95% CI of 4,564–216,952 (Conrad n.d.).

There are uncertainties regarding the point estimates of escapement derived by the newer M/R-based estimates, due to the positive bias that can occur from missed mark recoveries at fish traps or spawning grounds, under-estimates of post-tagging mortality or tag loss, size selectivity in the terminal test fisheries, or other issues (Cousens et al. 1982). The accuracy of the “marine survival*smolt outmigration”-based method is dependent upon the assumption that the Baker River natural-origin smolts survive and are exploited in fisheries at the same rate as the rest of the Skagit natural origin smolts, which may not be true. The veracity of the “test fishery hatchery/wild ratio”-based method is dependent upon an equal on the hatchery and wild populations. Due to unresolved uncertainties at this time regarding the accuracy of all the various available methods and associated estimates, the escapement estimates currently used by the co-managers for management purposes for the 1986-to-present period are an average of the annual results of the Base-Year Index and M/R (“Reverse Petersen”)-based estimates of escapement. Historical trends in escapement for the Skagit are provided in Figure 4.9. Known distribution of spawners within the basin is depicted in Figure NNN (derived from WDFW’s Salmonid Stock Inventory (SaSI) located at: http://wdfw.wa.gov/conservation/fisheries/sasi/).

Figure 4.9: Spawner distribution of Coho Salmon in the Skagit River Basin
Fishery Monitoring

A fundamental requirement of abundance-based Coho Salmon management under the is that all fishery impacts on individual be annually monitored with respect to both number of fish caught and CWTs. This requires basic reporting of total impacts by fishery and the capacity to estimate each fishery’s -specific impacts. Total fishing mortalities for each must be estimated to enable managers the ability to evaluate the annual relative to the -prescribed impact limits.

Assessments of total fishing mortalities for each must include both directed and incidentally-landed catch as well as estimates of non-landed mortalities. These estimates may be obtained through monitoring programs or, in some cases, generated through the use of algorithms built into the Fishery Regulation Assessment Model (FRAM). Monitoring programs may involve test fisheries or data collected directly from fishers (e.g., through creel survey interviews, and other fisher-reported techniques, such as log books or fish-tickets). Estimation of non-landed fishing mortality requires annual estimates of encounter rates by fishery and gear.

Mark-selective fisheries have been intensively monitored to collect data to estimate key parameters characterizing MSF fisheries and their impacts on unmarked salmon. Sampling activities include dockside creel sampling, on-water observation, and a Voluntary Trip Report (VTR) system. Data collected from this sampling is used to estimate key parameters necessary to manage fisheries and integrate MSFs in the FRAM model. These parameters include: mark rate of the targeted Coho Salmon populations; total number of Coho Salmon harvested or released by mark-status, the coded-wire-tag stock composition of landed Coho Salmon, and total mortality of marked and unmarked Coho.

Management impacts for each are generally evaluated using the coast-wide system. This system manages information on the release and recovery of coded-wire tags. The volume of tags recovered for a given will depend on tagging rates, marine survival rates, exploitation and escapement rates, and sampling rates in fisheries and escapements. A recent review of CWT methods (Pacific Salmon Commission Coded Wire Tag Workgroup 2008) recommends target sampling rates of 20% for the landed catch and 20% for escapements, with a minimum of 10 tags collected in each fishery or escapement stratum.

Post-season estimates are also generated using the Post-Season FRAM Model. Post-season estimates of catch and escapement are entered into the updated FRAM model with the same fishery regulation and effort package used for preseason modeling to generate post-season estimates.

Enhancement

There are numerous hatchery programs releasing Coho Salmon within the Skagit Basin. Since brood year 1983 to 2020, the largest ones include Marblemount, Baker Lake, Puget Sound Energy, and Swinomish Channel PD Hatchery programs. Over this time period approximately 690,000 Coho Salmon have been released annually on average. Marblemount Hatchery made up the majority (77%) of all releases, followed by Baker Lake Hatchery (9%), Puget Sound Energy (7%; ended with 2009 brood), and Swinomish Channel PD (2%; ended with 1990 brood). Prior to the implmentation of mass marking, total hatchery production within the of brood years 1983–1994 were highly variable, ranging from a high of three million fish released from brood year 1983 to a low of 380,000 fish from brood year 1988 (Figure ) (Pacific States Marine Fisheries Commission 1977). With the advent of technology to automatically remove adipose fins and/or insert using mobile “tagging trailers”, mass marking of hatchery fish was implemented for Coho Salmon in the mid-1990s (Selective Fishery Evaluation Committee 1999). Mass marking allows mark selective fisheries (MSF) for Coho Salmon in which marked hatchery fish can be retained and unmarked wild fish released, resulting in higher harvest rates on hatchery fish than wild fish. Mass marking was fully implemented for Coho Salmon from the Columbia River, Washington coast, and Puget Sound with the 1997 brood, including both mass marking (adipose fin clip) the vast majority of hatchery fish and use of select groups (paired clipped and unclipped fish with ) (Selective Fishery Evaluation Committee 1999). Double index tagging of hatchery fish at Marblemount Hatchery began with the 1994 brood and mass-marked fish were released beginning with brood year 1995. Hatchery production within the for brood years 1995 to brood year 2020 have averaged 500,000 annually, with a low of 252,000 in 2000 and a high of 795,000 in 2018. Of these, an average of 290,000 hatchery fish have been mass marked and released within the (fig_hatch_stock_releases_skagit) (Pacific States Marine Fisheries Commission 1977).

Figure 4.10: Hatchery production of Coho Salmon released within the Skagit , brood years 1983 through 2020.

4.2.1.3 Management Unit Performance

This section of the report includes summaries of forecast performance, abundances and abundance categories, and and associated impacting fisheries for the Skagit . Base period are also provided.

Forecast Evaluation

A comparison of preseason adult ocean age-3 recruit forecasts with post-season estimates derived from Backwards FRAM run reconstruction have been mixed, with some forecasts over estimating abundances and others underestimating it (Southern Panel –> do you wish to see a table of these data?). During catch years 2004–2021, predicted cohort size (without natural mortality) ranged from a low of 26,799 (2007) to a high of 155,814 (2004), while post-season estimates ranged from 11,521 (2006) to 145,283 (2004). Accordingly, the difference between preseason and post-season estimates varied from -210% (2007) to +89% (2006) of the preseason estimates.

Figure 4.11: Comparison of preseason abundance predictions with the post-season estimates for the Skagit MU.
Fishery Mortality and Escapement

Base Period Exploitation Rates The base period for the FRAM defines the temporal and spatial distributions of salmon fishing mortalities from each . The current FRAM base period for Coho Salmon includes catch years 1986-1992. During this period, fishing effort, tagging, and fishery sampling of Coho Salmon was high, allowing relatively fine-scale discrimination between salmon distributions. Coded-wire-tag codes used during the base period for the Skagit are provided **here* and average base period by individual fisheries are listed below.

During the base period, Coho Salmon production from the Skagit contributed to US and Canadian marine sport and commercial fisheries in southern British Columbia, the northern Washington coast, Strait of Juan de Fuca, and inner Puget Sound. Terminal tribal and non-tribal set and drift-net Coho Salmon net fisheries occur in commercial fishery management area 8 and the lower Skagit River. Moderate-sized Coho Salmon sport fisheries occured in sport fishery management area 8.1, the mainstem Skagit River, and the Cascade River. The terminal fishery co-managers are WDFW, and the Upper Skagit, Sauk-Suiattle, and Swinomish Tribes.

Skagit average annual (total) and time period specific used in the current FRAM base period. (CoTC –> is there a way to autobuild these tables directly from the FRAM database?)

      ||| Time Period || | |
** Fishery ** ** Jan-Jun ** ** Jul ** ** Aug ** ** Sept ** ** Oct-Dec ** ** Total **
SEAK Southwest Troll - 0.00% - - - 0.00%
BC Northern Net - 0.02% - - - 0.02%
BC Northern Troll - 0.02% 0.01% 0.01% - 0.04%
BC North Central Troll - 0.09% 0.01% - - 0.10%
BC Central Net - 0.01% 0.00% - - 0.02%
BC South Central Troll 0.14% 0.39% 0.05% 0.01% - 0.59%
Johnstone Strait Sport 0.02% 0.03% 0.01% - - 0.06%
Johnstone Strait Troll 0.04% 0.13% 0.01% 0.00% - 0.17%
Johnstone Straits Net - 0.01% 0.14% 0.04% 0.00% 0.18%
Georgia Straits Net - - 0.01% - 0.00% 0.02%
Georgia Straits Troll 0.14% 0.52% 0.07% 0.02% - 0.76%
North Georgia Straits Sport 1.41% 0.82% 0.41% 0.08% 0.00% 2.73%
South Georgia Straits Sport 0.71% 0.12% 0.11% 0.01% 0.02% 0.98%
Fraser R Gill Net - - 0.02% 0.01% - 0.03%
BC Juan de Fuca Net 0.02% 0.28% 3.75% 2.08% - 6.13%
BC Juan de Fuca Sport 0.63% 1.02% 0.35% 0.49% 0.10% 2.59%
BC Juan de Fuca Troll - 0.00% 0.00% 0.00% - 0.00%
West Coast Vanc Is Sport 0.02% 0.19% 0.07% 0.00% - 0.28%
NW Vancouver Island Troll 0.18% 3.16% 1.10% 0.33% - 4.77%
SW Vancouver Island Net 0.01% 0.00% - 0.12% 0.08% 0.21%
SW Vancouver Island Troll 0.84% 12.17% 6.61% 1.34% - 20.97%
WA Area 7 Sport 0.04% 0.06% 0.07% 0.09% 0.01% 0.26%
WA Area 7-7A Treaty Net - 0.00% 0.07% 0.30% 0.07% 0.44%
WA Area 7-7A Non-Treaty Net - 0.00% 0.07% 0.18% 0.03% 0.28%
WA Area 7B-7C-7D Treaty Net - - 0.01% 0.12% 0.11% 0.24%
WA Area 7B-7C-7D NT Net - - 0.00% 0.09% 0.08% 0.17%
WA Area 6 Sport 0.06% 0.30% 0.23% 0.49% 0.20% 1.28%
WA Area 5-6-6C Troll 0.00% 0.01% 0.01% 0.09% 0.00% 0.12%
WA Area 5 Sport 0.27% 0.97% 1.38% 1.18% 0.08% 3.88%
WA Area 4B-5-6C Treaty Net - 0.09% 0.29% 0.43% 0.21% 1.02%
WA Area 4B-5-6C NT Net - 0.00% 0.01% 0.04% 0.00% 0.05%
WA Area 8 Non-Treaty Net - - 0.11% 0.34% 0.79% 1.25%
WA Area 8 Treaty Net - - 0.08% 0.99% 1.56% 2.64%
WA Area 8.1 Sport - - 0.29% 0.02% 0.06% 0.37%
WA Area 8.2 Sport - - 0.05% 0.05% - 0.10%
Skagit R Net - - - - 0.93% 0.93%
Skagit R Sport - - - - 0.32% 0.32%
Skagit River Test Net - - - - 0.61% 0.61%
WA Area 8A Non-Treaty Net - - - 0.74% 0.63% 1.38%
WA Area 8A Treaty Net - - - 1.17% 0.94% 2.11%
WA Area 9 Sport 0.20% 0.23% 0.23% 0.38% 0.13% 1.16%
Area 9/9A Non-Treaty Net - - - 0.00% 0.00% 0.00%
Area 9/9A Treaty Net - - - 0.00% 0.01% 0.01%
WA Area 10 Non-Treaty Net - - - 0.41% 0.11% 0.52%
WA Area 10 Sport 0.15% 0.09% 0.07% 0.06% 0.02% 0.39%
WA Area 10 Treaty Net - - - 0.24% 0.06% 0.30%
WA Area 10E Non-Treaty Net - - - 0.00% - 0.00%
WA Area 10E Treaty Net - - - 0.00% - 0.00%
WA Area 10F-G Treaty Net - - 0.03% - - 0.03%
WA Area 11 Non-Treaty Net - - - 0.10% 0.02% 0.12%
WA Area 11 Sport 0.04% 0.00% 0.01% 0.00% 0.00% 0.06%
WA Area 11 Treaty Net - - - 0.01% 0.00% 0.01%
WA Area 13 Marine Sport 0.01% - - 0.00% 0.00% 0.02%
Area 12 Marine Sport - - - - 0.00% 0.00%
Area 12-12B Hood Canal NT Net - - - 0.01% 0.01% 0.02%
Area 12-12B Hood Canal T Net - - - 0.01% 0.01% 0.02%
WA Area 4/4B Treaty Troll 0.20% 0.62% 0.60% 0.21% 0.02% 1.66%
WA Area 4/4B Non-Treaty Troll 0.00% 0.04% 0.35% 0.06% 0.00% 0.45%
WA Area 4 Sport 0.02% 0.43% 0.34% 0.06% - 0.85%
WA Area 3 Treaty Troll 0.06% 0.13% 0.14% 0.05% - 0.38%
WA Area 3 Sport 0.00% 0.04% 0.01% - - 0.05%
WA Area 3 Non-Treaty Troll 0.05% 0.01% 0.04% 0.03% - 0.12%
Hoh R Net - - - - 0.00% 0.00%
WA Area 2 Treaty Troll 0.01% 0.09% 0.05% 0.01% - 0.16%
WA Area 2 Sport 0.03% 0.33% 0.15% 0.01% - 0.52%
WA Area 2 Non-Treaty Troll 0.01% 0.04% 0.06% 0.00% - 0.11%
Willapa Bay & FW Trib Net - - - - 0.00% 0.00%
WA Area 1 & Astoria Troll 0.01% 0.09% 0.05% 0.04% 0.01% 0.20%
WA Area 1 & Astoria Sport 0.00% 0.06% 0.05% - - 0.12%
Col. River Buoy 10 Sport - - 0.05% 0.00% - 0.06%
Tillamook Sport 0.01% 0.03% 0.02% 0.00% - 0.06%
Tillamook Troll 0.01% 0.17% 0.04% 0.00% - 0.22%
Newport Sport 0.02% 0.05% 0.03% - - 0.10%
Newport Troll 0.05% 0.12% 0.03% 0.00% - 0.21%
Coos Bay Sport 0.02% 0.02% 0.00% 0.01% - 0.05%
Coos Bay Troll 0.02% 0.03% 0.00% 0.00% - 0.06%
Brookings Sport - 0.00% - - - 0.00%
Brookings Troll 0.00% 0.00% 0.00% 0.00% - 0.01%
** Total ** 5.40% 23.10% 17.80% 12.60% 7.30% 66.10%

Current Exploitation Rates

Figure 4.12: Skagit post-season estimates of ocean age-3 abundances, escapement, and harvest for catch years 2004 through 2021. The graphs include dashed trend lines and the vertical dotted lines highlight catch year 2010)
Figure 4.13: Post-season estimates of fishery mortality for the Skagit by mark-selective (MSF) and non-selective (NS) fisheries over catch years 1998 through 2021. These estimates are combined US and Canadian harvest impacts.

Average by fishing area. The stacked bars represent the rates estimated by gear type during the FRAM base period, catch years 1986–1992. The line represents the average annual total by fishing area during catch years ??, all gears combined.

Total have generally declined, averaging 59% between 1986 and 1995 then gradually falling to an extended period of low (26%) during 1998–2004 (Table 5 1; Figure 4 2). have increased somewhat since 2005, averaging 36% during 2005–2011. Up until 1997 the by Canadian fishers averaged 36%, but has since declined to an average of less than 1.5%. A comparison of by major fisheries during the base period and the most recent five years (2006–2010) is provided in Figure 5 1, while by major fisheries by year since 1986 are listed in Appendix D. Individual fishery management areas within Washington State are depicted in Figure 5 2 and Figure 5 3.

To-do –> Add Table 5.1 (** this is the summary table with catch year, total abundance, escapement, marine survival from the static table, and US, Canada, and Total ER rates)

Historical summary of annual total abundance (January age-3 without natural mortality), adult escapement, marine survival (Baker River Wild), and (ER) of the Skagit Management Unit; since 1986.

Historical Overview of Status of Management Unit

Since catch year 2004, the post-season status of the Skagit has been “Moderate” or “Abundant”, except in 2006 when the estimate of age-3 ocean recruits was less than 12,000 fish (Table 7 1).

Estimated total abundance and escapement in the Skagit has been quite variable during 1986–2011, with a downward trend in total abundance and a slightly trend in escapement during this period. Total abundance has varied from low of 14,123 fish (2006) to a high of 397,120 fish (1986) and has exceeded 100,000 fish in 14 of 26 years between 1986 and 2011, and six times since 2000 (Table 5 1). Estimated escapement has averaged 54,275 during the entire time period and 55,364 during 2000–2011. It has varied from a low of 7,702 fish (2006) and a high of 118,220 (2004) (Table 5 1).

**Consider turning it into a table)

5 Members

Membership of the Joint Coho Technical Committee
Canadian Members United States Members
Ms. Dawn Lewis (Co-Chair), CDFO Dr. Gary S. Morishima (Co-Chair), QIN
Mr. Richard Bailey, Mr. John Brady, NOAA
Mr. Roger Dunlop, MMFN Ms. Carrie Cook-Tabor, USFWS
Mr. Kristopher Hein, CDFO Dr. Collin Edwards, WDFW
Ms. Sara Martin, CDFO Mr. Tyler Garber, WDFW
Mr. Michael O’Brien, CDFO Dr. Diego Holmgren, TUL
Mr. Kevin Pellet, CDFO Ms. Cassandra R. Leeman, ODFW
Ms. Ashlee Prevost, Dr. Marisa Litz, WDFW
Ms. Stephanie Thurner, NWIFC
Dr. Laurie Weitkamp, NMFS

6 Acronyms

Acronym Definition URL
ABM Abundance-Based Management
B.C. British Columbia
BkFRAM Backwards FRAM
BY Brood Year
CDFO Canadian Department of Fisheries and Oceans https://www.dfo-mpo.gc.ca/index-eng.htm
CFNC Canadian First Nations Caucus
CoTC Coho Joint Technical Committee https://www.psc.org/about-us/structure/committees/technical/coho/
CU Conservation Unit https://open.canada.ca/data/en/dataset/1ac00a39-4770-443d-8a6b-9656c06df6a3
CWT Coded-Wire Tag https://www.nmt.us/cwt/
DIT Double-Index Tag
EDT Electronic Tag Detection
ENSO El Niño-Southern Oscillation https://www.climate.gov/enso
ER Exploitation Rate
ESA U.S. Endangered Species Act https://www.fws.gov/international/laws-treaties-agreements/us-conservation-laws/endangered-species-act.html
ESU Evolutionarily Significant Unit https://www.nwfsc.noaa.gov/assets/4/6878_09172014_172219_Waples.1995.pdf
FMP Fisheries Management Plan
FRAFS Fraser River Aboriginal Fisheries Secretariat https://www.frafs.ca/
FRAM Fishery Regulation and Assessment Model https://framverse.github.io/fram_doc/
HC Hood Canal
IFMP Integrated Fisheries Management Plan https://www.pac.dfo-mpo.gc.ca/fm-gp/ifmp-eng.html#Salmon
IFR Interior Fraser River
iREC Internet-based Recreational Fishery https://www.pac.dfo-mpo.gc.ca/fm-gp/rec/irec-info-eng.html
JA3 January Age-3
LFFA Lower Fraser Fishery Alliance https://www.lffa.ca/
LWFR Lower Fraser River
MFMT Maximum Fishing Mortality Threshold
MMFN Mowachaht-Muchalaht First Nation https://www.yuquot.ca/
MSA Magnuson-Stevens Fishery Conservation and Management Act https://www.fisheries.noaa.gov/resource/document/magnuson-stevens-fishery-conservation-and-management-act
MSF Mark-Selective Fishery https://wdfw.wa.gov/sites/default/files/about/commission/meetings/2018/08/aug0918_fc_selective_fisheries.pdf
MSH Maximum Sustainable Harvest https://www.pcouncil.org/fact-sheet-annual-catch-limits-and-other-management-thresholds/#:~:text=The%20overfishing%20limit%20(OFL)%20is,the%20FMSY%20harvest%20rate.
MSM Mixed-Stock Model
MU Management Unit
NMFS National Marine Fisheries Service https://www.fisheries.noaa.gov/
NOF North of Falcon https://wdfw.wa.gov/fishing/management/north-falcon
NSF Non-Selective Fishery
NTC Nuu-chah-nulth Tribal Council https://nuuchahnulth.org/
NWIFC Northwest Indian Fisheries Commission https://nwifc.org/
OA3 Ocean Age-3
ODFW Oregon Department of Fish and Wildlife https://www.dfw.state.or.us/
OFL Overfishing Limit https://www.pcouncil.org/fact-sheet-annual-catch-limits-and-other-management-thresholds/#:~:text=The%20overfishing%20limit%20(OFL)%20is,the%20FMSY%20harvest%20rate.
OR Oregon
PDO Pacific Decadal Oscillation https://www.ncei.noaa.gov/access/monitoring/pdo/
PEF Production Expansion Factor
PFMC Pacific Fisheries Management Council U.S. https://www.pcouncil.org/
PS Puget Sound https://en.wikipedia.org/wiki/Puget_Sound
PSC Pacific Salmon Commission https://www.psc.org/
PST Pacific Salmon Treaty https://www.psc.org/publications/pacific-salmon-treaty/
QIN Quinault Indian Nation http://www.quinaultindiannation.com/
RMIS Regional Mark Information System https://www.rmpc.org/
RMISD Regional Mark Information System Database (U.S.) https://www.rmpc.org/
RMPC Regional Mark Processing Center https://www.rmpc.org/
RRTERM Terminal Area Run Reconstruction Program
SCMP Southern Coho Management Plan https://www.psc.org/publications/pacific-salmon-treaty/
SRSC Skagit River System Cooperative
SIT Single Index Tag
SJDF Strait of Juan de Fuca
SUQ Suquamish Tribe https://suquamish.nsn.us/
TT Tulalip Tribes https://www.tulaliptribes-nsn.gov/
U.S. United States
UFFCA Upper Fraser Fisheries Conservation Alliance https://www.upperfraser.ca/
USFWS U.S. Fish and Wildlife Service https://www.fws.gov/
WA Washington
WCVI West Coast of Vancouver Island
WDFW Washington Department of Fish and Wildlife https://wdfw.wa.gov/
WSP Wild Salmon Policy (Canada)
WRIA Water Resource Inventory Area (U.S.)

7 Glossary

Term Definition
Abundance-Based Management (ABM) A management framework that constrains exploitation rates, based on a categorical abundance forecast (abundant, moderate, low) for naturally-spawning Coho Management Units. The purpose is to provide more protection when the status of the fish is low and the conservation need is greatest, and more harvest opportunity when abundance is high. Exploitation rate caps are specified in the Pacific Salmon Treaty Southern Coho Agreement.
Base Period (FRAM) The FRAM base period is a period chosen to represent average temporal and geographic distributions of Coho Salmon coastwide. The base period was developed by summarizing coded-wire-tag information from a continuous time period containing a sufficient number of CWT releases and fishery recoveries. The current Coho base period is comprised of CWT recoveries from catch years 1986–1992. The Mixed-stock Model (MSM) and cohort reconstruction methods were used to estimate base period exploitation rates and other parameters, such as base period cohort sizes and fishery compositions, for all FRAM stocks and fisheries by time step. The base period is made up of the averages of these estimates over the catch years 1986 through 1992. Using these base period parameters allows FRAM to predict the stock composition, exploitation rates, and escapements of future fisheries when provided with forecasts of abundance and fishery mortalities.
Break point A Management Unit-specific ocean age-3 abundance level that determines the categorical status of a stock (i.e., abundant, moderate, low).
Brood Year (BY) The year in which the majority of parent fish spawned and deposited fertilized eggs.
By-catch Incidental or unintentional catch of non-target stocks or species.
Catch The number of fish that are retained in a fishery.
Coded-Wire Tag (CWT) A small piece of magnetized stainless-steel wire that is injected into the snout of a juvenile salmon (usually hatchery stock). Each tag is 0.25 mm in diameter and typically 1.1 mm long and is etched with a code that identifies its specific release group. Each code is associated with release information, including date and location of release, hatchery, stock, fish size, and number of fish tagged with that same code (referred to as a release group). Tags are typically recovered from returning adults through fishery and escapement sampling. Release and recovery Information is stored in the U.S. in the Regional Mark Information System's (RMIS) Release database and in Canada’s Mark Recovery Program.
Cohort A group of fish belonging to the same brood year.
Cohort Abundance For each stock unit, an annual abundance is obtained from a regional expert, typically in the form of an ocean age-3 run size (pre-fishing age-3 abundance in the ocean after natural mortality has been subtracted). In a pre-season context these abundances come from annual forecasts, whereas in a post-season context the abundances are derived from estimates of actual returns. For Coho, an initial stock abundance is needed for adult fish (age-3) by mark status.
Cohort Reconstruction or Cohort Analysis Cohort reconstruction is a method commonly used in salmon stock assessment for estimation of exploitation rates. The basic principle of cohort reconstruction is the sequential estimation of a cohort’s abundance from the end of the cohort’s life span, when abundance is zero, to a specified earlier age (commonly age-3 for Coho). A full cohort reconstruction can be completed only once the cohort’s life span has ended. Age-specific escapement and harvest data are required and, in general, the natural mortality rates are assumed.
Co-management The collaborative process between co-managers–tribal governments and state governments on the West Coast. Using scientific information, the co-managers make decisions about the management of fisheries to ensure that the fisheries meet legal requirements, treaty fishing rights, and conservation goals.
Command Files The files used in the Fisheries Regulation Assessment Model containing all the necessary input parameters to run the model, such as forecasted abundance estimates and fishery regulations. A separate command file is developed for each FRAM run.
Conservation Unit (CU) Salmon populations that have been identified as distinct units of biodiversity under the Canadian Wild Salmon Policy (see Holtby and Ciruna 2007). A Conservation Unit (CU) is a group of wild Pacific salmon sufficiently isolated from other groups that, if extirpated, is very unlikely to recolonize naturally within an acceptable timeframe, such as a human lifetime or a specified number of salmon generations.
Double-Index Tag (DIT) Paired groups of tagged fish, each tagged with separate CWT tag code, used to determine differential exploitation rates on marked and unmarked fish subjected to mark-selective fisheries. Both groups are presumed identical except that one group is externally marked (adipose fin clipped) and one group is unmarked (not adipose fin clipped).
El Niño Index (ONI) The Oceanic Niño Index (ONI) is an index for tracking the ocean part of ENSO, the El Niño-Southern Oscillation climate pattern. The ONI is a rolling 3-month average temperature anomaly in the surface waters of the east-central tropical Pacific, near the International Dateline. Index values of +0.5 or higher indicate El Niño. Values of -0.5 or lower indicate La Niña.
Electronic Tag Detection (ETD) The use of a handheld wand or tunnel type detector that can sense the magnetized coded-wire tag within a fish's snout.
Endangered Species Act (U.S.) The Endangered Species Act (ESA) is the primary law in the United States for protecting critically important species that are at risk of extinction. Under the ESA, the federal government has the responsibility to protect these species and their critical habitats. NOAA Fisheries is responsible for endangered and threatened salmon.
Enhancement Use of hatcheries, spawning channels, lake fertilization or habitat restoration to increase the survival rate or production of salmon at some stage of its life.
Escapement (Spawning Escapement) The number of adult salmon that escape all fisheries and other forms of mortality to return to a hatchery or stream to spawn.
Evolutionarily Significant Unit (ESU) Under the U.S. Endangered Species Act, a group of Pacific salmon populations that represent an important component of the evolutionary legacy of the species and are therefore treated as a single “species”.
Exclusive Economic Zone The Exclusive Economic Zone (EEZ) is an area from 3 to 200 nautical miles offshore of coastal states and is classified as federal waters. In the EEZ, the U.S. has special rights about the exploration and use of marine resources, which includes energy production from water and wind, and fisheries.
Exploitation Rate (ER) Expressed as a percentage, the proportion of the total return of adult salmon in a given year that die as a result of fishing activity. Mortalities include landed catch and incidental mortalities.
Exploitation Rate Cap The maximum exploitation rate an MU can be subjected to given its categorical abundance status. Under the ABM, allowable exploitation rate is shared by Canada and the U.S.
Fisheries Management Fisheries management is a process that relies on science, management approaches, enforcement, partnerships, and public participation. Fisheries management uses scientific information (e.g., number of fish caught, types of fish caught, life cycle knowledge) and input from fishing communities to help guide management decisions and conservation objectives.
Fisheries Management Plan (FMP) The set of fisheries planned to distribute exploitation rates amongst fisheries and time periods each year. These are termed Integrated Fisheries Management Plans in Canada.
Fishery A fishery is an activity leading to the harvesting of fish and can be specified by the species of fish caught, people involved, location, method of fishing, and purpose of the activities. Fish caught in a fishery can be for commercial, recreational, or tribal and ceremonial purposes.
Fishery Regulation Assessment Model (FRAM) A model used to estimate the MU- and fishery-specific impacts. The Forwards FRAM projects MU-specific mortalities and escapements under proposed fishery regimes given pre-season forecasts. The Backwards Coho FRAM estimates unspecified MU abundances using estimates of escapements and fishing mortalities. It includes 246 stocks, 198 fisheries, and 5 time steps.
Fry Salmon that have emerged from gravel, completed yolk absorption, remained in freshwater streams, and are less than a few months old.
FSC (Canada) First Nations' fishery for food, social, and ceremonial use.
Harvest The term harvest refers to the total number of fish caught and kept from an area or fishery during a period of time.
Incidental mortality Mortality incurred during fishing in addition to landed catch. For example, some fish die as a result of being caught and released.
Indicator stock A coded-wire-tagged surrogate stock that is used to make inferences for a particular MU. For example, a CWT release from a hatchery stock may be used to estimate the distribution and magnitude of fishing mortalities.
Integrated Fisheries Management Plan (IFMP) These Canadian plans identify the main objectives and requirements for Pacific fisheries and outline the management to achieve these objectives. IFMPs provide a common understanding of the basic rules for the sustainable management of the fisheries resource, and communicate basic information about fish stocks and our fisheries.
Interception Interception occurs when a salmon from one state or country is caught in another state or country's fisheries. As salmon grow and mature in the Pacific Ocean, they travel along the West Coast and across international borders. Salmon that originate in U.S. streams may migrate through Canadian waters, where they may be caught in Canadian fisheries. Salmon from Oregon streams can be caught in Washington fisheries.
January age-3 abundance (JA3) The estimated abundance of fish of age-3 (adults) in January before any fisheries start. January age-3 abundance is estimated as fishing mortality plus escapement plus natural mortality.
La Niña
Landed catch Fish that are caught and kept (see Incidental mortality)
Magnuson-Stevens Fishery Conservation and Management Act (MSA) The Magnuson-Stevens Fishery Conservation and Management Act (MSA) is the primary law that governs fisheries management in the federal marine waters (3-200 miles offshore) of the United States. The goal of the MSA is to encourage the long-term biological and economic sustainability of marine fisheries.
Management Unit (MU) Under the PST Southern Coho agreement, a geographically-based aggregate of salmon populations, that is managed under a single set of exploitation rate caps.
Mark-Selective Fishery (MSF) A fishery that requires marked fish (i.e., those with adipose fin clips) and unmarked fish (those with intact adipose fins) to be differentially retained (e.g., marked fish kept, unmarked fish released).
Maximum Sustainable Harvest (MSH) An estimate of the largest average annual catch or yield that can be continuously taken over a long period from a stock under prevailing ecological and environmental conditions.
Mixed-Stock Model A model used to estimate the cohort abundances in mixed stock fisheries using coded-wire tags and estimates of catch (see Production Expansion Factors).
Naturally Produced Originated from spawning in the natural environment, as opposed to spawned in a hatchery. Often considered “wild”.
Non-retention fisheries Fisheries in which a particular group of fish are not allowed to be kept (e.g., due to species or external marks) (see Retention Fisheries)
Non-selective fisheries (NSF) Fisheries allowed to retain both marked (adipose fin clipped) and unmarked fish (see Mark-selective fishery).
North of Falcon Each year state, federal, and tribal fishery managers gather to plan the Northwest's recreational and commercial salmon fisheries. This series of meetings – involving representatives from federal, state and tribal governments and recreational and commercial fishing industries – is known as the North of Falcon process. The North of Falcon planning process coincides with the March and April meetings of the Pacific Fishery Management Council (PMFC), the federal authority responsible for setting ocean salmon seasons 3 to 200 miles off the Pacific coast. In addition to the two PFMC meetings, the states of Washington and Oregon and the Treaty Tribes sponsor additional meetings to discuss alternative fishing seasons that meet conservation and allocation objectives. Fishery managers generally refer to the entire set of pre-season meetings as North of Falcon. The name refers to Cape Falcon in northern Oregon, which marks the southern border of active management for Washington salmon stocks.
Ocean Age-3 Abundance (OA3) Total number of fish that are harvested (including incidental mortality) plus those that escape to spawn (also referred to as “cohort abundance” or “ocean recruits”). Natural mortality is not included. This abundance status of a Management Unit is based upon this estimate of abundance.
Overfishing Limit (OFL) The overfishing limit (OFL) is the maximum amount of a stock that can be caught in a year without resulting in overfishing. Groundfish OFLs for assessed stocks are typically determined by multiplying the estimated abundance of the exploitable biomass of a stock by the FMSY harvest rate. There are also methods for determining OFLs for unassessed stocks. Setting OFLs is a scientific (as opposed to policy) determination made by the Scientific and Statistical Committee (SSC). OFLs are set for every actively managed stock or stock complex.
Pacific Decadal Oscillation (PDO) The PDO describes the pattern of sea surface temperatures around the North Pacific Ocean north of 20°N. During a "warm", or "positive", phase, the west Pacific becomes cooler and part of the eastern ocean warms; during a "cool", or "negative", phase, the opposite pattern occurs. The index was originally described by Mantua et al. 1997 (Bulletin of the American Meteorological Society. 78 (6): 1069–79.)
Pacific Salmon Commission (PSC) A joint Canada/U.S. commission established under the Pacific Salmon Treaty to oversee the implementation of the Pacific Salmon Treaty.
Pacific Salmon Treaty (PST) A treaty between Canada and the United States concerning the conservation, management, restoration, and enhancement of pacific salmon resources.
Pacific States Marine Fisheries Commission (PSMFC) Pacific States Marine Fisheries Commission (PSMFC) is a non‐regulatory agency that serves Alaska, California, Idaho, Oregon, and Washington. PSMFC (headquartered in Portland) administers salmon disaster relief funds, provides a communication exchange between the Pacific Fishery Management Council and the North Pacific Fishery Management Council, and provides information in the form of data services for various fisheries.
Production Expansion Factor (PEF) A scalar that represents the number of fish in a population from a single CWT recovery.
Rebuilding The process of rebuilding an overfished stock. For salmon, rebuilding usually takes the form of reduced harvest limits.
Reference Point A Management Unit-specific ocean age-3 abundance level that determines the categorical status of a stock (i.e., abundant, moderate, low).
Regional Mark Information System (RMIS) Database containing data on salmonid releases, recoveries in fisheries and escapement, and estimated catch by fishery and time period.
Retention fisheries Fisheries in which fish of a particular group are allowed to be kept (see Non-retention fisheries).
Return year The year in which fish would normally return to spawn as adults. For Southern Coho Salmon that mature as 3 year old adults, return year is Brood Year + 3.
RR Term A program that reconstructs terminal Coho runs using freshwater and terminal area marine fisheries and escapement data for Puget Sound stocks.
Run As salmon migrate back to freshwater as adults, they arrive in groups called runs, which are typically associated with a season (spring, summer, fall, winter). A run of salmon may be composed of salmon from a single age or multiple ages, and can be from a single stock or multiple stocks.
Sibling Forecast In all species of Pacific salmon but pinks, the individual salmon produced in any one spawning year mature and return to spawn in more than one subsequent year. All of the fish that return from a spawning year (the brood year) are collectively referred to as a cohort or the brood-year return. A sibling forecast uses the first returns from a cohort to predict the number of their siblings that will return in subsequent years. Generally, the first year of return is dominated by males and the last year of returns by females.
Single Index Tag (SIT) A group of coded-wire-tagged (CWT) fish that are not paired with another release group. They can be marked (clipped) or unmarked (unclipped).
Smolt A smolt is a life cycle phase of a salmon or steelhead when the fish is preparing for the transition from freshwater to saltwater. The process is called smoltification. A smolt becomes physiologically capable of balancing salt and water in the estuary and ocean waters. Smolts vary in size and age depending on the species of salmon.
Smolt Year The year in which fish would normally enter the ocean as smolts. For Southern Coho Salmon, smolt year is brood year + 2 and return year − 1. Often described as “smolt outmigration year”.
Southern Coho Management Plan (SCMP) An agreement between the U.S. and Canada that specifies how the Parties’ fisheries impact on Coho Salmon that originate in southern British Columbia, Washington and Oregon shall be managed, subject to future approved technical refinements. It is described in Annex IV, Chapter 5 of the current Pacific Salmon Treaty.
Spawning Escapement The number of adult fish that “escape” fisheries and return to freshwater to spawn.
Spawning Grounds/Spawn Spawning grounds are the freshwater areas where salmon and steelhead spawn.
Special management zone (SMZ) Geographic/temporal areas in B.C. that have special management restrictions.
Status A Management Unit's status (Low, Moderate, and Abundant) is based on its forecasted (pre-season) or estimated (post-season) ocean Age-3 abundance.
Stock A group of interbreeding organisms that is relatively isolated (i.e., demographically uncoupled) from other such groups and is likely adapted to the local habitat. Fish species are made up of an aggregate of stocks.
Stock Assessment The use of various statistical and mathematical calculations to make quantitative predictions about the reactions of fish populations to alternative management choices.
Subsistence Fisheries In the Pacific Northwest of the U.S., the term "Ceremonial and Subsistence" (C&S) is used to describe non-commercial harvest in Treaty Tribe fisheries for personal, ritual, or community use. In Canada, the term "Food, Social, and Ceremonial" (FSC) is used to describe the non-commercial harvest of fish by the First Nations.
Treaty/Treaties A treaty is a formal, legally binding agreement that establishes obligations between and among two or more countries, states, or sovereign nations. Examples of treaties include the Pacific Salmon Treaty and treaties between the U.S. and American Indian Tribes.
Troll Fishery (Trolling) Fishing with a hook or hooks attached to a line that is towed through the water or from a vessel. Commercial trollers employ hooks and lines that are suspended from large poles extending from the fishing vessel
Voluntary Head Recovery Program (VHRP) A sampling program in B.C. for recreational fisheries that relies upon anglers voluntarily returning heads from marked salmon so CWTs may be recovered.
Wild Salmon Salmon are considered "wild" if they have spent their entire life cycle in the wild and originate from parents that were also produced by natural spawning and continuously lived in the wild.

8 Appendix: Annual CoTC reports of Estimates of Exploitation Rates

General archive of public CoTC reports

9 Appendix: DITs

9.1 Skagit

Table 9.1: Double-index tag codes released within the Skagit MU, brood years 1994 through 2021
Brood Year Hatchery DIT Group ID Tag Code Mark # Released
1994 MARBLEMOUNT HATCHERY 04199600000211 635909 Clipped 99623
1994 MARBLEMOUNT HATCHERY 04199600000211 635906 Unclipped 45865
1995 MARBLEMOUNT HATCHERY 04199700000212 636158 Clipped 42489
1995 MARBLEMOUNT HATCHERY 04199700000212 636201 Unclipped 42566
1996 MARBLEMOUNT HATCHERY 04199800000196 630545 Clipped 43348
1996 MARBLEMOUNT HATCHERY 04199800000196 630546 Unclipped 45089
1997 MARBLEMOUNT HATCHERY 04199900000195 630554 Clipped 42299
1997 MARBLEMOUNT HATCHERY 04199900000195 636211 Unclipped 41906
1998 MARBLEMOUNT HATCHERY 04200000000209 631107 Clipped 40398
1998 MARBLEMOUNT HATCHERY 04200000000209 631108 Unclipped 40525
1999 MARBLEMOUNT HATCHERY 04200100000199 630299 Clipped 45831
1999 MARBLEMOUNT HATCHERY 04200100000199 630298 Unclipped 45052
2000 MARBLEMOUNT HATCHERY 04200200000200 630950 Clipped 10582
2000 MARBLEMOUNT HATCHERY 04200200000200 630387 Clipped 10777
2000 MARBLEMOUNT HATCHERY 04200200000200 630946 Clipped 10783
2000 MARBLEMOUNT HATCHERY 04200200000200 630948 Clipped 10861
2000 MARBLEMOUNT HATCHERY 04200200000200 630386 Unclipped 10988
2000 MARBLEMOUNT HATCHERY 04200200000200 630947 Unclipped 10969
2000 MARBLEMOUNT HATCHERY 04200200000200 630949 Unclipped 10935
2000 MARBLEMOUNT HATCHERY 04200200000200 630945 Unclipped 10988
2001 MARBLEMOUNT HATCHERY 04200300000206 631257 Clipped 10745
2001 MARBLEMOUNT HATCHERY 04200300000206 631259 Clipped 11240
2001 MARBLEMOUNT HATCHERY 04200300000206 631253 Clipped 9013
2001 MARBLEMOUNT HATCHERY 04200300000206 631255 Clipped 9975
2001 MARBLEMOUNT HATCHERY 04200300000206 631254 Unclipped 7472
2001 MARBLEMOUNT HATCHERY 04200300000206 631069 Unclipped 6887
2001 MARBLEMOUNT HATCHERY 04200300000206 631256 Unclipped 9063
2001 MARBLEMOUNT HATCHERY 04200300000206 631258 Unclipped 8999
2002 MARBLEMOUNT HATCHERY 04200400000192 632090 Clipped 11046
2002 MARBLEMOUNT HATCHERY 04200400000192 632088 Clipped 10781
2002 MARBLEMOUNT HATCHERY 04200400000192 632089 Clipped 6947
2002 MARBLEMOUNT HATCHERY 04200400000192 632091 Clipped 10861
2002 MARBLEMOUNT HATCHERY 04200400000192 632092 Unclipped 10967
2002 MARBLEMOUNT HATCHERY 04200400000192 632094 Unclipped 10878
2002 MARBLEMOUNT HATCHERY 04200400000192 632093 Unclipped 9781
2002 MARBLEMOUNT HATCHERY 04200400000192 632095 Unclipped 11100
2003 MARBLEMOUNT HATCHERY 04200500000191 631997 Clipped 46348
2003 MARBLEMOUNT HATCHERY 04200500000191 632289 Unclipped 46823
2004 MARBLEMOUNT HATCHERY 04200600000183 633099 Clipped 47305
2004 MARBLEMOUNT HATCHERY 04200600000183 633197 Unclipped 41300
2005 MARBLEMOUNT HATCHERY 04200700000184 633571 Clipped 43100
2005 MARBLEMOUNT HATCHERY 04200700000184 633572 Unclipped 43575
2006 MARBLEMOUNT HATCHERY 04200800000187 633691 Clipped 47072
2006 MARBLEMOUNT HATCHERY 04200800000187 633690 Unclipped 47206
2007 MARBLEMOUNT HATCHERY 04200900000180 634484 Clipped 44174
2007 MARBLEMOUNT HATCHERY 04200900000180 634485 Unclipped 44604
2008 MARBLEMOUNT HATCHERY 04201000000181 634495 Clipped 43359
2008 MARBLEMOUNT HATCHERY 04201000000181 634496 Unclipped 43568
2009 MARBLEMOUNT HATCHERY 04201100000213 635381 Clipped 44465
2009 MARBLEMOUNT HATCHERY 04201100000213 635382 Unclipped 43354
2010 MARBLEMOUNT HATCHERY 04201200000215 635799 Clipped 41840
2010 MARBLEMOUNT HATCHERY 04201200000215 635798 Unclipped 42100
2011 MARBLEMOUNT HATCHERY 04201300000030 636377 Clipped 45068
2011 MARBLEMOUNT HATCHERY 04201300000030 636376 Unclipped 45650
2012 MARBLEMOUNT HATCHERY 04201400000080 636555 Clipped 43388
2012 MARBLEMOUNT HATCHERY 04201400000080 636554 Unclipped 43163
2013 MARBLEMOUNT HATCHERY 04201500000796 636697 Clipped 47575
2013 MARBLEMOUNT HATCHERY 04201500000796 636696 Unclipped 47670
2014 MARBLEMOUNT HATCHERY 04201600000837 636839 Clipped 43867
2014 MARBLEMOUNT HATCHERY 04201600000837 636840 Unclipped 43868
2015 MARBLEMOUNT HATCHERY 04201700000878 636993 Clipped 46326
2015 MARBLEMOUNT HATCHERY 04201700000878 636994 Unclipped 46309
2016 MARBLEMOUNT HATCHERY 04201800000906 637089 Clipped 36508
2016 MARBLEMOUNT HATCHERY 04201800000906 637088 Unclipped 36893
2017 MARBLEMOUNT HATCHERY 04201900000951 637272 Clipped 41744
2017 MARBLEMOUNT HATCHERY 04201900000951 637271 Unclipped 41842
2018 MARBLEMOUNT HATCHERY 04202000001028 637555 Clipped 44326
2018 MARBLEMOUNT HATCHERY 04202000001028 637554 Unclipped 46243
2019 MARBLEMOUNT HATCHERY 04202100001068 637678 Clipped 41895
2019 MARBLEMOUNT HATCHERY 04202100001068 637677 Unclipped 42653
2020 MARBLEMOUNT HATCHERY 04202200001130 638003 Clipped 40507
2020 MARBLEMOUNT HATCHERY 04202200001130 638002 Unclipped 40547
2021 MARBLEMOUNT HATCHERY 04202300001147 638230 Clipped 45944
2021 MARBLEMOUNT HATCHERY 04202300001147 638229 Unclipped 45747
2022 MARBLEMOUNT HATCHERY 04202400001224 638131 Clipped 41738
2022 MARBLEMOUNT HATCHERY 04202400001224 638130 Unclipped 47290

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Footnotes

  1. Beginning BY 1996, all tagged releases were unmarked.↩︎

  2. BYs 1997 and 1998, all tagged releases were unmarked; fry released BYs 84-90 and 93.↩︎

  3. BYs 1999, 2001-02, and 2005, all tagged releases were unmarked; fry released BY 1995.↩︎

  4. BYs 1997 and 1998 were released as fry.↩︎

  5. When space is limited at Spius Creek Hatchery, additional fish are raised at Chilliwack River Hatchery and released in the Coldwater River.↩︎

  6. Fry released BYs 1983-1990.↩︎

  7. All fry releases.↩︎

  8. All fry releases.↩︎

  9. Beginning BY 1998, all tagged releases were unmarked; fry released BY 1987, 1989-90.↩︎

  10. BY 1997 released unmarked; fry released BY 1984-86, 1988.↩︎

  11. Beginning BY 1997, all tagged releases were unmarked; fry released BY 1983-86, 1988.↩︎

  12. Beginning BY 1997, all tagged releases were unmarked; fry released BY 1988-89.↩︎

  13. Begging BY 2000, all tagged releases were unmarked.↩︎

  14. All tagged releases were unmarked.↩︎

  15. Fry released BY 1989.↩︎

  16. Fry released BYs 2009-10.↩︎

  17. Beginning with BY 1997 (except 2004) tagged releases were unmarked.↩︎

  18. Beginning BY 1996, all tagged releases were unmarked.↩︎

  19. Bernie Gobin Hatchery tagging program and the Skykomish tagging program at the Wallace River Hatchery are used to represent production in both the Stillaguamish and Snohomish River Basins.↩︎

  20. BY 1997-98 were released unmarked; this stock was used to represent Stillaguamish in the FRAM base period.↩︎

  21. BY 1996 and 1998-2020, all tagged releases were unmarked.↩︎

  22. Fry released BY 1986.↩︎

  23. Release groups were very small.↩︎

  24. In all years, release groups are very small. Beginning BY 2003, all tagged releases were unmarked.↩︎

  25. Beginning BY 1996, all tagged releases were unmarked.↩︎

  26. Beginning BY 1995, all tagged releases were unmarked.↩︎

  27. Beginning BY 1995, all tagged releases were unmarked.↩︎